Electrochemical systems with electronically conductive layers

ABSTRACT

Provided are separator systems for electrochemical systems providing electronic, mechanical and chemical properties useful for a variety of applications including electrochemical storage and conversion. Embodiments provide structural, physical and electrostatic attributes useful for managing and controlling dendrite formation and for improving the cycle life and rate capability of electrochemical cells including silicon anode based batteries, air cathode based batteries, redox flow batteries, solid electrolyte based systems, fuel cells, flow batteries and semisolid batteries. Disclosed separators include multilayer, porous geometries supporting excellent ion transport properties, providing a barrier to prevent dendrite initiated mechanical failure, shorting or thermal runaway, or providing improved electrode conductivity and improved electric field uniformity. Disclosed separators include composite solid electrolytes with supporting mesh or fiber systems providing solid electrolyte hardness and safety with supporting mesh or fiber toughness and long life required for thin solid electrolytes without fabrication pinholes or operationally created cracks.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. Nonprovisional patentapplication Ser. No. 13/545,683, filed Jul. 10, 2012, which claims thebenefit of, and priority, to U.S. Provisional Application No.61/506,489, filed Jul. 11, 2011 and U.S. Provisional Application No.61/622,371, filed Apr. 10, 2012, and PCT International ApplicationPCT/US12/46067, filed Jul. 10, 2012, which claims the benefit of, andpriority, to U.S. Provisional Application No. 61/506,489, filed Jul. 11,2011 and U.S. Provisional Application No. 61/622,371, filed Apr. 10,2012; this application also claims the benefit of, and priority to, U.S.Provisional Application No. 61/622,371, filed Apr. 10, 2012, U.S.Provisional Application No. 61/677,306, filed Jul. 30, 2012, and U.S.Provisional Application No. 61/679,584, filed Aug. 3, 2012, all of whichare hereby incorporated by reference their entireties to the extent notinconsistent with the present description.

BACKGROUND

Over the last few decades revolutionary advances have been made inelectrochemical storage and conversion devices expanding thecapabilities of these systems in a variety of fields including portableelectronic devices, air and space craft technologies, passenger vehiclesand biomedical instrumentation. Current state of the art electrochemicalstorage and conversion devices have designs and performance attributesthat are specifically engineered to provide compatibility with a diverserange of application requirements and operating environments. Forexample, advanced electrochemical storage systems have been developedspanning the range from high energy density batteries exhibiting verylow self-discharge rates and high discharge reliability for implantedmedical devices to inexpensive, light weight rechargeable batteriesproviding long runtimes for a wide range of portable electronic devicesto high capacity batteries for military and aerospace applicationscapable of providing extremely high discharge rates over short timeperiods.

Despite the development and widespread adoption of this diverse suite ofadvanced electrochemical storage and conversion systems, significantpressure continues to stimulate research to expand the functionality ofthese systems, thereby enabling an even wider range of deviceapplications. Large growth in the demand for high power portableelectronic products, for example, has created enormous interest indeveloping safe, light weight primary and secondary batteries providinghigher energy densities. In addition, the demand for miniaturization inthe field of consumer electronics and instrumentation continues tostimulate research into novel design and material strategies forreducing the sizes, masses and form factors of high performancebatteries. Further, continued development in the fields of electricvehicles and aerospace engineering has also created a need formechanically robust, high reliability, high energy density and highpower density batteries capable of good device performance in a usefulrange of operating environments.

Many recent advances in electrochemical storage and conversiontechnology are directly attributable to discovery and integration of newmaterials for battery components. Lithium battery technology, forexample, continues to rapidly develop, at least in part, due to thediscovery of novel electrode and electrolyte materials for thesesystems. The element lithium has a unique combination of properties thatmake it attractive for use in an electrochemical cell. First, it is thelightest metal in the periodic table having an atomic mass of 6.94 AMU.Second, lithium has a very low electrochemical oxidation/reductionpotential (i.e., −3.045 V vs. NHE (normal hydrogen referenceelectrode)). This unique combination of properties enables lithium basedelectrochemical cells to have very high specific capacities. State ofthe art lithium ion secondary batteries provide excellentcharge-discharge characteristics, and thus, have also been widelyadopted as power sources in portable electronic devices, such ascellular telephones and portable computers. U.S. Pat. Nos. 6,852,446,6,306,540, 6,489,055, and “Lithium Batteries Science and Technology”edited by Gholam-Abbas Nazri and Gianfranceo Pistoia, Kluer AcademicPublishers, 2004, which are hereby incorporated by reference in theirentireties, are directed to lithium and lithium ion battery systems.

Advances in electrode materials, electrolyte compositions and devicegeometries continue to support the further development of Li basedelectrochemical systems. For example, U.S. Patent ApplicationPublication US2012/0077095, published on Mar. 29, 2012, andInternational Patent Application publication WO 2012/034042, publishedon Mar. 15, 2012, disclose three-dimensional electrode array structuresfor electrochemical systems including lithium batteries.

Despite substantial advances, practical challenges remain in connectionwith the continued development of Li based electrochemical systems. Asignificant issue, for example, relates to dendrite formation in primaryand secondary lithium and lithium ion batteries. It is generally knownthat Li deposition in many electrolytes is highly dendritic which makethese systems susceptible to problems involving shorting, mechanicalfailure and thermal runaway. Safety concerns relating to dendriteformation are currently a barrier to implementation of metal Li anodesin rechargeable systems. A number of strategies have been pursued toaddress safety in connection with dendrite formation, particularly inthe context of secondary batteries, including development of non-lithiumanodes and internal safety systems able to monitor in real time problemsassociated with dendrite formation.

As will be generally recognized from the foregoing, a need currentlyexists for electrochemical systems, such as lithium based or alkalinebased batteries, flow batteries, supercapacitors and fuel cells,exhibiting electrochemical properties useful for a range ofapplications. Specifically, lithium electrochemical systems capable ofgood electrochemical performance and high versatility for both primaryand secondary lithium based batteries are needed.

SUMMARY

In an aspect, the invention provides separator systems forelectrochemical systems providing electronic, mechanical and chemicalproperties useful for a range of electrochemical storage and conversionapplications. Separator systems of some embodiments, for example,provide structural, physical and electrostatic attributes useful forpreventing catastrophic failure in electrochemical cells and useful forincreasing the performance such as cycle life and energy and power. Oneseries of examples are separators for managing and controlling dendriteformation in metal based batteries, such as lithium based, alkalinebased, zinc based and lead based batteries. In an embodiment, forexample, separator systems of the invention have a multilayer, porousgeometry supporting excellent ion transport properties while at the sametime providing a barrier effective to prevent dendrite initiatedmechanical failure, electronic internal shorting and/or thermal runaway.Another series of examples are multilayer separators consisting ofseveral porous/perforated layers and an impervious yet ion-selectiveconductive membrane in which the porous layers provide a barriereffective to prevent internal shorting failure, such as dendriteshorting failure, and/or thermal runaway; and the membrane layer providea barrier effective to separate the electrolyte next to the anode fromthat next to the cathode which can prevent the contamination of eitherof the electrodes and their surfaces and their electrolytes and thusincrease the performance of the cell, such as energy, power and lifecycle; this is especially useful in metal air and flow batteries andsemi-solid batteries, some examples are lithium-air, lithium water andzinc-air cells.

In an embodiment, the invention provides a separator system for anelectrochemical system comprising: (i) a first high mechanical strengthlayer having a plurality of apertures extending entirely through thefirst high mechanical strength layer and provided in a first pattern;and (ii) a second high mechanical strength layer having a plurality ofapertures extending entirely through the second high mechanical strengthlayer and provided in a second pattern; the second pattern having anoff-set alignment relative to the first pattern such that an overlap ofthe apertures of the first high mechanical strength layer and theapertures of the second high mechanical strength layer along axesextending perpendicularly from the first high mechanical strength layerto the second high mechanical strength layer is less than or equal to20%; wherein the first high mechanical strength layer and the secondhigh mechanical strength layer are positioned such that ions of anelectrolyte provided in contact with the first high mechanical strengthlayer and the second high mechanical strength layer are able to betransported through the first high mechanical strength layer and thesecond high mechanical strength layer. In an embodiment, for example,the first high mechanical strength layer and the second high mechanicalstrength layer are not in direct physical contact with each other. In anembodiment of this aspect, the overlap of the apertures of the firsthigh mechanical strength layer and the apertures of the second highmechanical strength layer along axes extending perpendicularly from thefirst high mechanical strength layer to the second high mechanicalstrength layer is less than or equal to 10%. In an embodiment, forexample, the separator system of the invention further comprises one ormore electrolytes provided between, and optionally in contact, with thefirst high mechanical strength layer the second high mechanical strengthlayer or both, wherein the first and second high mechanical strengthlayers are ionically conductive and optionally allow transport of theelectrolyte of an electrochemical system.

In an embodiment, the invention provides a separator system for anelectrochemical system comprising: (i) a first high mechanical strengthlayer having a plurality of apertures extending entirely through thefirst high mechanical strength layer and provided in a first pattern;(ii) a second high mechanical strength layer having a plurality ofapertures extending entirely though the second high mechanical strengthlayer and provided in a second pattern, the second pattern having anoff-set alignment relative to the first pattern such that an overlap ofthe apertures of the first high mechanical strength layer and theapertures of the second high mechanical strength layer along axesextending perpendicularly from the first high mechanical strength layerto the second high mechanical strength layer is less than or equal to20%; and (iii) a third high mechanical strength layer having a pluralityof apertures extending entirely through the third high mechanicalstrength layer and provided in a third pattern having the same spatialarrangement of apertures as the first pattern; wherein the first highmechanical strength layer, the second high mechanical strength layer andthe third high mechanical strength layer are positioned such that ionsof an electrolyte provided in contact with the first high mechanicalstrength layer, the second high mechanical strength layer and the thirdhigh mechanical strength layer are able to be transported through thefirst high mechanical strength layer, the second high mechanicalstrength layer and the third high mechanical strength layer. In anembodiment of this aspect, the overlap of the apertures of the firsthigh mechanical strength layer and the apertures of the second highmechanical strength layer along axes extending perpendicularly from thefirst high mechanical strength layer to the second high mechanicalstrength layer is less than or equal to 10%. As used throughout thisdescription, the “same spatial arrangement of apertures” refers to thepositions of apertures of two or more high mechanical strength layerssuch that they are aligned along axes extending perpendicularly betweenthe high mechanical strength layers. In an embodiment, for example, thesame spatial arrangement of apertures” refers to the positions ofapertures of two or more high mechanical strength layers such that theyoverlap by a factor of 90% or more along axes extending perpendicularlybetween the high mechanical strength layers.

In an embodiment, the invention provides a separator system for anelectrochemical system comprising: (i) a first high mechanical strengthlayer having a plurality of apertures extending entirely through thefirst high mechanical strength layer and provided in a first pattern;(ii) a second high mechanical strength layer having a plurality ofapertures extending entirely through the second high mechanical strengthlayer and provided in a second pattern, the second pattern having anoff-set alignment relative to the first pattern such that an overlap ofthe apertures of the first high mechanical strength layer and theapertures of the second high mechanical strength layer along axesextending perpendicularly from the first high mechanical strength layerto the second high mechanical strength layer is less than or equal to20%; (iii) a third high mechanical strength layer having a plurality ofapertures extending entirely through the third high mechanical strengthlayer and provided in a third pattern having the same spatialarrangement of apertures as that of the first pattern; and (iv) a fourthhigh mechanical strength layer having a plurality of apertures extendingentirely through the fourth high mechanical strength layer and providedin a fourth pattern having the same spatial arrangement of apertures asthat of the second pattern; wherein the first high mechanical strengthlayer, the second high mechanical strength layer, the third highmechanical strength layer and the fourth high mechanical strength layerare positioned such that ions of an electrolyte provided in contact withthe first high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer and the fourthhigh mechanical strength layer are able to be transported through thefirst high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer and the fourthhigh mechanical strength layer. In an embodiment of this aspect, theoverlap of the apertures of the first high mechanical strength layer andthe apertures of the second high mechanical strength layer along axesextending perpendicularly from the first high mechanical strength layerto the second high mechanical strength layer is less than or equal to10%.

In an embodiment, the invention provides a separator system for anelectrochemical system comprising: (i) a first high mechanical strengthlayer having a plurality of apertures extending entirely through thefirst high mechanical strength layer and provided in a first pattern;(ii) a second high mechanical strength layer having a plurality ofapertures extending entirely through the second high mechanical strengthlayer and provided in a second pattern, the second pattern having anoff-set alignment relative to the first pattern such that an overlap ofthe apertures of the first high mechanical strength layer and theapertures of the second high mechanical strength layer along axesextending perpendicularly from the first high mechanical strength layerto the second high mechanical strength layer is less than or equal to40%; and (iii) a third high mechanical strength layer having a pluralityof apertures extending entirely through the third high mechanicalstrength layer and provided in a third pattern; the third pattern havingan off-set alignment relative to the first pattern and the secondpattern such that an overlap of the apertures of the first highmechanical strength layer, the apertures of the second high mechanicalstrength layer and the apertures of the third high mechanical strengthlayer along axes extending perpendicularly from the first layer or thesecond layer to the third layer is less than or equal to 20%; whereinthe first high mechanical strength layer, the second high mechanicalstrength layer and the third high mechanical strength layer arepositioned such that ions of an electrolyte provided in contact with thefirst high mechanical strength layer, the second high mechanicalstrength layer and the third high mechanical strength layer are able tobe transported through the first high mechanical strength layer, thesecond high mechanical strength layer and the third high mechanicalstrength layer. In an embodiment of this aspect, the overlap of theapertures of the first high mechanical strength layer and the aperturesof the second high mechanical strength layer along axes extendingperpendicularly from the first high mechanical strength layer to thesecond high mechanical strength layer is less than or equal to 20% andthe overlap of the apertures of the first high mechanical strengthlayer, the apertures of the second high mechanical strength layer andthe apertures of the third high mechanical strength layer along axesextending perpendicularly from the first high mechanical strength layeror the second high mechanical strength layer to the third highmechanical strength layer is less than or equal to 10%.

In an embodiment, the invention provides a separator system for anelectrochemical system comprising: (i) a first high mechanical strengthlayer having a plurality of apertures extending entirely through thefirst high mechanical strength layer and provided in a first pattern;(ii) a second high mechanical strength layer having a plurality ofapertures extending entirely through the second high mechanical strengthlayer and provided in a second pattern, the second pattern having anoff-set alignment relative to the first pattern such that an overlap ofthe apertures of the first high mechanical strength layer and theapertures of the second high mechanical strength layer along axesextending perpendicularly from the first high mechanical strength layerto the second high mechanical strength layer is less than or equal to50%; (iii) a third high mechanical strength layer having a plurality ofapertures extending entirely through the third high mechanical strengthlayer and provided in a third pattern; the third pattern having anoff-set alignment relative to the first pattern and the second patternsuch that an overlap of the apertures of the first high mechanicalstrength layer, the apertures of the second high mechanical strengthlayer and the apertures of the third high mechanical strength layeralong axes extending perpendicularly from the first high mechanicalstrength layer or the second high mechanical strength layer to the thirdhigh mechanical strength layer is less than or equal to 30%; and (iv) afourth high mechanical strength layer having a plurality of aperturesextending entirely through the fourth high mechanical strength layer andprovided in a fourth pattern; the fourth pattern having an off-setalignment relative to the first pattern, the second pattern and thethird pattern such that an overlap of the apertures of the first highmechanical strength layer, the apertures of the second high mechanicalstrength layer, the apertures of the third high mechanical strengthlayer and the apertures of the fourth high mechanical strength layeralong axes extending perpendicularly from the first high mechanicalstrength layer or the second high mechanical strength layer to thefourth high mechanical strength layer is less than or equal to 20%;wherein the first high mechanical strength layer, the second highmechanical strength layer, the third high mechanical strength layer andthe fourth high mechanical strength layer are positioned such that ionsof an electrolyte provided in contact with the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer and the fourth high mechanical strengthlayer are able to be transported through the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer and the fourth high mechanical strengthlayer. In an embodiment of this aspect, the overlap of the apertures ofthe first high mechanical strength layer and the apertures of the secondhigh mechanical strength layer along axes extending perpendicularly fromthe first high mechanical strength layer to the second high mechanicalstrength layer is less than or equal to 30%, and the off-set alignmentrelative to the first pattern and the second pattern such that anoverlap of the apertures of the first high mechanical strength layer,the apertures of the second high mechanical strength layer and theapertures of the third high mechanical strength layer along axesextending perpendicularly from the first layer or the second layer tothe third layer is less than or equal to 20%, and off-set alignmentrelative to the first pattern, the second pattern and the third patternsuch that an overlap of the apertures of the first high mechanicalstrength layer, the apertures of the second high mechanical strengthlayer, the apertures of the third high mechanical strength layer and theapertures of the fourth high mechanical strength layer along axesextending perpendicularly from the first high mechanical strength layeror the second high mechanical strength layer to the third layer is lessthan or equal to 10%.

In some embodiments, for example, the second high mechanical strengthlayer is provided between the first high mechanical strength layer andthe third high mechanical strength layer. In some embodiments, forexample, the first high mechanical strength layer is provided betweenthe second high mechanical strength layer and the fourth high mechanicalstrength layer or wherein the third high mechanical strength layer isprovided between the second high mechanical strength layer and thefourth high mechanical strength layer. In an embodiment, first andsecond mechanical strength layers are not provided in physical contact,or first, second and third mechanical strength layers are not providedin physical contact, or first, second, third and fourth mechanicalstrength layers are not provided in physical contact.

Some separators of this aspect, for example, provide a multilayerstructure for managing dendrite formation in an electrochemical system,wherein multiple separator layers (e.g., first, second, third, fourth,etc. high mechanical strength layers) have complementary patterns ofapertures, such as micro- or nano-channels, that establish ionconductivity between positive and negative electrodes in a manner thatdendrite growth between positive and negative electrodes is kineticallyand/or thermodynamically unfavorable. Some separators of this aspect,for example, provide a barrier having a multilayer geometry and physicalproperties preventing a direct, linear pathway for dendrite growthbetween positive and negative electrodes, for example, by providing amultilayer structure wherein the only pathway(s) for ion transportbetween positive a negative electrodes requires curved trajectories thatare kinetically and/or thermodynamically unfavorable to dendrite growth.Without being bound by any theory, the force from the high strengthlayers on the dendrites slows down or stops the dendrite growth. Inelectrochemical cell embodiments, this significantly improves theperformance of the cell. In an embodiment, the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer and/or the fourth high mechanicalstrength layer are planar and provided in a substantially parallelorientation with respect to each other, for example, wherein planarsurfaces of the first, second, third and/or fourth high mechanicalstrength layers are provided in parallel planes. In an embodiment, thefirst high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer and/or thefourth high mechanical strength layer are hollow cylindrical structuresand provided in a substantially concentric orientation, for example,wherein curved surfaces of cylindrical first and second layers areprovided in a concentric orientation. As used herein, axes extendingperpendicularly from a concentric orientation are perpendicular to acentral axis and extend radially from the central axis.

The multilayer geometry of some separator systems of the inventionprovides an off-set alignment providing a selected overlap of aperturesof the first pattern and the apertures of the second pattern along axesextending perpendicularly from the first layer to the second layer. Thisaspect of the invention is useful for accessing useful ion transportproperties while at the same time preventing dendrite formation betweenpositive and negative electrodes of an electrochemical cell. In someembodiments, the term “off-set” refers to a configuration wherein theapertures of one high mechanical strength layer of the separator areoff-set relative to the positions of apertures of another highmechanical strength layer along axes extending from the one layer to theanother layer, such as axes extending perpendicularly from a first highmechanical strength layer to a second high mechanical strength layer. Insome embodiments, the term “off-set” refers to a relative configurationof patterns of apertures in high mechanical strength layers, such aswherein the apertures of a first pattern of the first high mechanicalstrength layer are off-set relative to the positions of apertures of thesecond pattern of the second high mechanical strength layer such thatthe apertures of the first high mechanical strength layer are notentirely superimposable onto the apertures of the second high mechanicalstrength layer along the axes extending perpendicularly from the firsthigh mechanical strength layer to the second high mechanical strengthlayer. In an embodiment, for example, the first and second highmechanical strength layers are nano- and/or micro-porous and alignedsuch that the apertures of the first high mechanical strength layer arenot superimposable at all onto the apertures of the second highmechanical strength layer along the axes extending perpendicularly fromthe first high mechanical strength layer to the second high mechanicalstrength layer. In an embodiment, for example, the overlap of theapertures of two or more of the first pattern, the second pattern, thethird pattern and the fourth pattern along the axes extendingperpendicularly from the first high mechanical strength layer to thesecond high mechanical strength layer is less than or equal to 10%, andoptionally for some applications less than or equal to 1%. In anembodiment, for example, the overlap of the apertures of two or more ofthe first pattern, the second pattern, the third pattern and the fourthpattern along the axes extending perpendicularly from the first highmechanical strength layer to the second high mechanical strength layeris selected from the range of 0 to 5%, and optionally for someapplications selected from the range of 0 to 1%. In an embodiment, forexample, the overlap of the apertures of two or more of the firstpattern, the second pattern, the third pattern and the fourth patternalong the axes extending perpendicularly from the first high mechanicalstrength layer to the second high mechanical strength layer is equal to0, for example equal to 0 by a good precision. In an embodiment, forexample, the overlap of the apertures of the first pattern, the secondpattern, and the third pattern along the axes extending perpendicularlyfrom the first high mechanical strength layer to the second highmechanical strength layer is less than or equal to 10%. In anembodiment, for example, the overlap of the apertures of the firstpattern, the second pattern, and the third pattern along the axesextending perpendicularly from the first high mechanical strength layerto the second high mechanical strength layer is selected from the rangeof 0 to 5%. In an embodiment, for example, the overlap of the aperturesof the first pattern, the second pattern, the third pattern and thefourth pattern along the axes extending perpendicularly from the firsthigh mechanical strength layer to the second high mechanical strengthlayer is less than or equal to 10%. In an embodiment, for example, theoverlap of the apertures of the first pattern, the second pattern, thethird pattern and the fourth pattern along the axes extendingperpendicularly from the first high mechanical strength layer to thesecond high mechanical strength layer is selected from the range of 0 to5%.

In an embodiment, for example, two or more of the first pattern, thesecond pattern, the third pattern and the fourth pattern comprisesubstantially complementary patterns. In an embodiment, for example, thesubstantially complementary patterns correspond to substantiallynegative images of one another. As used herein, a complementary patternrefers to a configuration wherein the relative positions of apertures ofone pattern of a high mechanical strength layer and the apertures of oneor more other pattern or one or more other high mechanical strengthlayers are selected to prevent dendrite growth between positive andnegative electrodes of an electrochemical cell. In an embodiment, forexample, the substantially complementary patterns of the first andsecond patterns are negative images of one another, for example, whereinthe positions of apertures of the first pattern correspond to regions ofthe second layer not having an aperture. As an example of acomplementary pattern of the invention, the first layer may becharacterized by a pattern of apertures corresponding to the blacksquares of a chess board and the second layer may be characterized by apattern of apertures corresponding to the red squares of the chessboard. As an example of a complementary pattern of the invention, thefirst high mechanical strength layer may have a first periodic patternof apertures characterized by a first pitch and aperture spacing,wherein the second high mechanical strength layer has a second periodicpattern of apertures characterized by a the same pitch and aperturespacing but offset or translated from the positions of the apertures ofthe first pattern such that the apertures of the first high mechanicalstrength layer are not superimposable on the apertures of the secondhigh mechanical strength layer along axes extend perpendicularly fromfirst and second high mechanical strength layers.

In an embodiment, a separator system having three or more highmechanical strength layers may include some high mechanical strengthlayers having identical patterns (i.e. non-complementary patterns), solong as at least one layer having a complementary pattern is positionedbetween the high mechanical strength layers having identical patterns.For example, a separator system may be characterized by one or more highmechanical strength layers having a pattern A and one or more highmechanical strength layers having a pattern B, where A and B arecomplementary patterns, arranged according to a repeating sequence ofABA, with longer sequences possible for multilayer systems containingfour or more high mechanical strength layers, e.g., ABABAB.

In another embodiment, a separator system having three or more highmechanical strength layers may include only high mechanical strengthlayers having complementary patterns. For example, a separator systemmay be characterized by one or more high mechanical strength layershaving a pattern A, one or more high mechanical strength layers having apattern B, and one or more high mechanical strength layers having apattern C, where A, B and C are each complementary to the other twopatterns, arranged according to a repeating sequence of ABC, with longersequences (e.g. ABCABC) and varied sequences (e.g. ABCBA, ABCA) possiblefor multilayer systems containing four or more high mechanical strengthlayers.

In another aspect, the invention provides separator systems furthercomprising one or more low ionic resistance layers provided on a side ofat least one of the first high mechanical strength layer, the secondhigh mechanical strength layer, the third high mechanical strength layerand the fourth high mechanical strength layer. In an embodiment, forexample, each of the one or more low ionic resistance layers is anelectrolyte containing layer providing a reservoir for the electrolyte,for example of an electrochemical cell. In an embodiment, for example,each of the one or more low ionic resistance layers independently has anionic resistance less than or equal to 20 ohm-cm², and preferably forsome embodiments less than or equal to 2 ohm-cm²′ and preferably forsome embodiments less than or equal to 1 ohm-cm². In an embodiment, forexample, at least one of t one or more low ionic resistance layers is apressure buffer providing space for an electrolyte provided between atleast two of the first high mechanical strength layer, the second highmechanical strength layer, the third high mechanical strength layer andthe fourth high mechanical strength layer.

In an embodiment, for example, at least one of the high mechanicalstrength layers and the one or more low ionic resistance layers is adeposited layer that is deposited on at least one of the high mechanicalstrength layers and the one or more low ionic resistance layers. In anembodiment, for example, at least one of the high mechanical strengthlayers and the one or more low ionic resistance layers is a depositedlayer that is deposited on an electrode of an electrochemical cell, suchas a layer deposited directly on the surface of a positive or negativeelectrode presented to an electrolyte of an electrochemical cell. In anembodiment, for example, at least one of the one or more low ionicresistance layers, and optionally all, is adhered by pressure, heat orchemical adhering to at least one side of any of the first highmechanical strength layer, the second high mechanical strength layer,the third high mechanical strength layer and the fourth high mechanicalstrength layer. In an embodiment, for example, at least one of the oneor more low ionic resistance layers, and optionally all, is adhered by aresin polymer to at least one side of any of the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer and the fourth high mechanical strengthlayer. In an embodiment, for example, at least one of the one or morelow ionic resistance layers, and optionally all, comprises a microporousmaterial, a woven material, or a nonwoven material.

In an embodiment, for example, at least one of the one or more low ionicresistance layers, and optionally all, comprises a ceramic or a glasselectrolyte, a polymer electrolyte or another solid electrolyte. In anembodiment, for example, the low ionic resistance layers comprise aglass electrolyte, such as Nafion or ZrO₂ or NASICON or LISICON orLIPON, or a polymer electrolyte such as PEO. In an embodiment, forexample, at least one of the one or more low ionic resistance layers,and optionally all, comprises a perforated ceramic separator, a porousceramic separator, a perforated glass separator, a porous glassseparator or a perforated metal or perforated alloy separator orperforated rubber or a rubber mesh or a metal mesh or an alloy mesh or aporous metal.

In an embodiment, for example, at least one of the one or more low ionicresistance layers comprises a ring or a frame having a central aperture,such as a ring or frame structure providing a mechanically supportingstructure, an electrolyte reservoir structure and/or a spacer structurein an electrochemical cell. In an embodiment, for example, the one ormore low ionic resistance layers comprise one or more frame layers incontact with at least one of the first high mechanical strength layer,the second high mechanical strength layer, the third high mechanicalstrength layer and the fourth high mechanical strength layer. In anembodiment, for example, the first high mechanical strength layer isprovided between first and second frame layers and wherein the secondhigh mechanical strength layer is provided between third and fourthframe layers or the first high mechanical strength layer is providedbetween first and second frame layers and wherein the second highmechanical strength layer is provided between second and third framelayers. In an embodiment, for example, the one or more low ionicresistance layers comprise one or more frame layers in physical contactwith at least one of the electrodes of an electrochemical system, suchas the positive and/or negative electrodes of an electrochemical cell.In an embodiment, for example, the one or more low ionic resistancelayers comprise a spacer provided between the first and second layers,the spacer separating the first and second layers by a selected distanceselected from the range of 10 nm to 1000 μm, and optionally for someapplications selected from the range of 1 μm to 1000 μm. In anembodiment, for example, the spacer of this aspect comprises: a ring forestablishing the selected distance between the first high mechanicalstrength layer and the second high mechanical strength layer; a framestructure having a porous wall component, a material layer, or anarrangement of discrete material elements.

In an embodiment, for example, each of the low ionic resistance layers,and optionally all, is independently a polymer, a ceramic, a wood,glass, a mineral, a metal, an alloy, a woven material, a nonwovenmaterial, cellulose, wood fiber, sponge or a combination thereof. In anembodiment, for example, the one or more low ionic resistance layerseach independently have porosity greater than or equal to 50%, andpreferably for some applications greater than 70%, and preferably forsome applications greater than 90%. In an embodiment, for example, theone or more low ionic resistance layers each independently have aporosity selected from the range of 50% to 95%, preferably for someapplications a porosity selected from the range of 70% to 95%.

In an embodiment, for example, at least one side of one of the highmechanical strength layers is wet-able, for example wet-able withelectrolyte of an electrochemical cell. In an embodiment, for example, aseparator configuration is characterized by the wet-able side of a highmechanical strength layer is placed next to another high mechanicalstrength layer with no low ionic resistance layer provided between them.In an embodiment, for example, a separator configuration ischaracterized by the wet-able side of the high mechanical strength layeris placed next to an electrode with no low ionic resistance layerbetween them. In an embodiment, for example, a separator includes one ormore low ionic resistance layers or high mechanical strength layerscoated on another low ionic resistance layer or a high mechanicalstrength layer or coated on an electrode in a chemical cell, such as onthe positive electrode or negative electrode of an electrochemicalsystem.

In another aspect, the invention provides a separator further comprisingone or more chemical barrier layers provided on a side of at least oneof the first high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer, the fourthhigh mechanical strength layer or the one or more low ionic resistancelayers. Separators having one or more chemical barriers are useful inelectrochemical systems wherein positive and negative electrodes areprovided in contact with different electrolytes and, thus, the chemicalbarrier(s) allow transport of charge carriers but prevents transport ofelectrolytes. In such configurations, the chemical barriers are usefulfor protecting the electrodes from degradation and/or enabling the useof different electrolytes for positive and negative electrodes of anelectrochemical cell. In an embodiment, for example, the one or morechemical barrier layers independently prevents transportation ofunwanted chemical components through the one or more chemical barrierlayers to a positive electrode or a negative electrode of anelectrochemical cell. In an embodiment, for example, the one or morechemical barrier layers prevents transport of an electrolyte solventthrough the one or more chemical barrier layers to a positive electrodeor a negative electrode of an electrochemical cell. In an embodiment,for example, the one or more chemical barrier layers comprises a solidelectrolyte or a solid polymer electrolyte disposed on at least one sideof an electrode of an electrochemical cell. In an embodiment, forexample, the one or more chemical barrier layers comprise a solidelectrolyte from LISICON or NASICON or a polymer electrolyte comprisingpolyethylene oxide (PEO).

In an embodiment, for example, the separator system is a component of anelectrochemical cell having a negative electrode and a positiveelectrode, wherein the one or more chemical barrier layer comprise anion conductive protective membrane, wherein the protective membraneprovides a barrier between a first electrolyte in contact with thepositive electrode and a second electrode in contact with the negativeelectrode, wherein the ion conductive protective membrane preventscontact between the negative electrode and the first electrolyte. In anembodiment, for example, the negative electrode is a lithium metalelectrode, wherein the ion conductive protective membrane conductslithium ion charge carriers and prevents contact between the lithiummetal electrode and the first electrolyte.

In an embodiment, for example, the ion conductive protective membranecomprising a material selected from the group consisting of glassy oramorphous active metal ion conductors, ceramic active metal ionconductors, and glass-ceramic active metal ion conductors. In anembodiment, for example, the one or more chemical barrier layers furthercomprises a solid polymer electrolyte disposed between a surface of theprotective membrane and the positive electrode or negative electrode. Inan embodiment, for example, at least one of the high mechanical strengthlayers, one or more low ionic resistance layers and the one or morechemical barrier layers is a deposited layer that is deposited on atleast one of the high mechanical strength layers, one or more low ionicresistance layers and the one or more chemical barrier layers. In anembodiment, for example, at least one of the high mechanical strengthlayers, one or more low ionic resistance layers and the one or morechemical barrier layers is a deposited layer that is deposited on anelectrode of an electrochemical cell. In an embodiment, for example, aseparator comprises a combination of at least two of the first highmechanical strength layer, the second high mechanical strength layer,the third high mechanical strength layer and the fourth high mechanicalstrength layer and the one or more chemical barrier layers without anyof the low ionic resistance layers.

In an aspect, a separator further comprises a third high mechanicalstrength layer having a plurality of apertures extending entirelythrough the third high mechanical strength layer and provided in a thirdpattern; the third high mechanical strength layer positioned between thefirst high mechanical strength layer and the second high mechanicalstrength layer; the third pattern having an off-set alignment relativeto the first pattern or the second pattern such that an overlap of theapertures of the first pattern or the second pattern and the aperturesof the third pattern along axes extending perpendicularly from the firsthigh mechanical strength layer or the second high mechanical strengthlayer to the third high mechanical strength layer is less than or equalto 20%. In an aspect, a separator further comprises a fourth highmechanical strength layer having a plurality of apertures extendingentirely through the fourth high mechanical strength layer and providedin a fourth pattern; the fourth high mechanical strength layerpositioned between the first high mechanical strength layer and thesecond high mechanical strength layer, the fourth pattern having anoff-set alignment relative to the first pattern, the second pattern orthe third pattern such that an overlap of the apertures of the firstpattern, the second pattern or the third pattern and the apertures ofthe fourth pattern along axes extending perpendicularly from the firsthigh mechanical strength layer or the second high mechanical strengthlayer to the fourth high mechanical strength layer is less than or equalto 20%.

The layers of multilayer separator systems of the invention may beconfigured and attached via a variety of mechanisms and devicearrangements to provide mechanical properties useful for specificapplications. In an embodiment, for example, at least a portion, andoptionally all, of the first high mechanical strength layer, the secondhigh mechanical strength layer, the third high mechanical strengthlayer, the fourth high mechanical strength layer, low ionic resistancelayers, frame layers, spacer, chemical barrier layers, or anycombination of these are at least partially attached to each other via apressure, heating, an adhesive coating, a chemical adherent, plasmatreating or any combination of these. In an embodiment, for example, atleast a portion, and optionally all, of the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer, the fourth high mechanical strengthlayer, low ionic resistance layers, frame layers, spacer, chemicalbarrier layers, or any combination of these are at least partiallyattached to each other via glue, epoxy, cement, PTFE, a solidelectrolyte, a gel electrolyte, a polymer electrolyte, a siliconeadhesive, acrylic adhesive, cyanacrylate, stycast 1266, deltabond 151,PVDF, PVA, LIPON, LISICON, PE-PP-PVDF, tetramethylammonium hydroxidepentahydrate (CH₃)₄NOH.5H₂O, poly(ethylene oxide) (PEO), copolymer ofepichlorohydrin and ethylene oxide P(ECH-co-EO) and poly(vinylalcohol),glassfibre polymer electrolyte, zinc sulfide, silicon dioxide, KaptonTape, polyethylene oxide or polypropylene oxide, or a copolymer,PVDF-co-HFP Bi₂O₃, a non-fluorine-containing binder or an aromaticbinder, lithium polyacrylate or a combination thereof.

In an embodiment, the invention provides a separator system furthercomprising one or more solid electrolyte layers that prevent watermolecules, CO₂, O₂ or air from transporting through the separatorsystem, for example, wherein the one or more solid electrolyte layerscomprise LISICON or NASICON.

In an aspect, a separator of the invention further comprises one or moreelectrolytes, such as an electrolyte of an electrochemical cell, whichis optionally in physical contact with at least a portion of the firsthigh mechanical strength layer, the second high mechanical strengthlayer, the third high mechanical strength layer, the fourth highmechanical strength layer, low ionic resistance layers, frame layers,spacer, chemical barrier layers, or any combination of these. In anembodiment, for example, the separator system is a component of anelectrochemical cell having a positive electrode and a negativeelectrode, the separator further comprising an electrolyte providedbetween the positive electrode and the negative electrode; wherein theelectrolyte is in contact with any of the first high mechanical strengthlayer, the second high mechanical strength layer, the third highmechanical strength layer, and the fourth high mechanical strengthlayer. In an embodiment, for example, the separator system is acomponent of an electrochemical cell having a positive electrode and anegative electrode, the separator further comprising a first electrolyteand a second electrolyte provided between the positive electrode and thenegative electrode; wherein the first electrolyte has a differentcomposition than the second electrolyte; wherein the first electrolyteis in contact with any of the first high mechanical strength layer, thesecond high mechanical strength layer, the third high mechanicalstrength layer, and the fourth high mechanical strength layer, andwherein the second electrolyte is in contact with any of the first highmechanical strength layer, the second high mechanical strength layer,the third high mechanical strength layer, and the fourth high mechanicalstrength layer; where the first electrolyte and the second electrolytedo not mix with each other because of the presence of an impervious ionconducting layer between them or because of different chemistry andphysics such as hydrophilic or hydrophobic behavior or density.

Selection of the physical, chemical and electronic properties of thecomponents of the separator system, such as the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer, and the fourth high mechanical strengthlayer, are selected to provide net separator properties useful forapplications in electrochemical cells, such as to provide thecombination of high electrical resistance, high ion conductivity anduseful mechanical attributes.

In an embodiment, for example, the first pattern of apertures provides afirst porosity of the first high mechanical strength layer greater thanor equal to 30% and preferably for some applications more than 40%,and/or wherein the second pattern of apertures provides a secondporosity of the second high mechanical strength layer greater than orequal to 30%, and preferably for some applications more than 40%. In anembodiment, for example, the first pattern of apertures provides a firstporosity of the first high mechanical strength layer greater than orequal to 30% and preferably for some applications more than 40%, orwherein the second pattern of apertures provides a second porosity ofthe second high mechanical strength layer greater than or equal to 30%and preferably for some applications more than 40%; or wherein the thirdpattern of apertures provides a third porosity of the third highmechanical strength layer greater than or equal to 30% and preferablyfor some applications more than 40%; or wherein the fourth pattern ofapertures provides a fourth porosity of the fourth high mechanicalstrength layer greater than or equal to 30% and preferably for someapplications more than 40%. In an embodiment, for example, the firstpattern of apertures provides a porosity of the first high mechanicalstrength layer selected from the range of 30% to 70% and preferably forsome applications 40% to 70%; and wherein the second pattern ofapertures provides a porosity of the second high mechanical strengthlayer selected from the range of 30% to 70% and preferably for someapplications 40% to 70%. In an embodiment, for example, the firstpattern of apertures provides a porosity of the first high mechanicalstrength layer selected from the range of 30% to 70% and preferably forsome applications 40% to 70%; or wherein the second pattern of aperturesprovides a porosity of the second high mechanical strength layerselected from the range of 30% to 70% and preferably for someapplications 40% to 70%; or wherein the third pattern of aperturesprovides a porosity of the third high mechanical strength layer selectedfrom the range of 30% to 70% and preferably for some applications 40% to70%; or wherein the fourth pattern of apertures provides a porosity ofthe fourth high mechanical strength layer selected from the range of 30%to 70% and preferably for some applications 40% to 70%.

A range of geometries, shapes, orientations and patterns for aperturesof the high mechanical strength layers are useful in the separatorsystems of the invention. In an embodiment, for example, the aperturesof any of the first high mechanical strength layer, the second highmechanical strength layer, the third high mechanical strength layer orthe fourth high mechanical strength layer independently have crosssectional shapes selected from the group consisting of a circle,parallelogram, rectangle, square, triangle, ellipse, tetragon, pentagon,hexagon and any combinations thereof. In an embodiment, for example, theapertures of the high mechanical strength layers have at least onelateral dimension (e.g., length, width, diameter, etc.) greater than orequal to 20 μm, optionally for some embodiments greater than or equal to50 μm, optionally for some embodiments greater than or equal to 200 μm;optionally for some embodiments greater than or equal to 500 μm. In anembodiment, for example, the apertures of the high mechanical strengthlayers have at least one lateral dimension between 1 μm and 1 mm, andoptionally for some applications 200 μm and 1 mm. In an embodiment, forexample, the apertures of the high mechanical strength layers have atleast one lateral dimension less than or equal to 200 μm and optionallyfor some applications less than or equal to 10 μm; and optionally forsome applications less than or equal to 1 μm. In an embodiment, forexample, any of the first pattern, the second pattern, the third patternor the fourth pattern is independently a symmetrical pattern ofapertures or an asymmetrical pattern of apertures. In an embodiment, forexample, any of the first pattern, the second pattern, the third patternor the fourth pattern independently comprise a pattern of apertures thatis not random.

In an embodiment, for example, any of the first pattern of apertures,second pattern of apertures, third pattern of apertures or the fourthpattern of apertures are independently made by a process selected fromthe group consisting of laser cutting, lithography, etching, casting,drilling, molding, punching, patterning, coating and any combinations ofthese.

In an embodiment, the first high mechanical strength layer; and/orsecond high mechanical strength layer; and/or third high mechanicalstrength layer; and/or fourth high mechanical strength layer areelectrically non-conductive, for example, one or more of these layerscomprising an electrically insulating material so as to prevent directelectrical contact between positive and negative electrodes of anelectrochemical system such as an electrochemical cell. Electricallyinsulating high mechanical strength layers may comprise a range ofelectrical insulating materials such as Kapton, polyester, Al₂O₃,polyethylene, Polypropylene, fibrous cellulose, and/or metal layerscoated with electrical insulators such as PE and PP coatings. In anembodiment, at least one of the first high mechanical strength layer;and/or second high mechanical strength layer; and/or third highmechanical strength layer; and/or fourth high mechanical strength layerare electrically conductive, for example, wherein one or more of theselayers comprises an electrically insulating material and one or more ofthese layers comprises an electrically conductive material. the firsthigh mechanical strength layer; and/or second high mechanical strengthlayer; and/or third high mechanical strength layer; and/or fourth highmechanical strength layer comprise a material characterized by a shapememory property, such as a shape memory polymer, or a materialscharacterized by the property of super elasticity.

In an embodiment, for example, the first high mechanical strength layerand the second high mechanical strength layer are not in completephysical contact with each other, such as provided in a configurationwherein there is at least some space between first high mechanicalstrength layer and the second high mechanical strength layer forelectrolyte to have ionic transport, such as provided by first andsecond high mechanical strength layers having rough surfaces in contactwith each other such that at some points they are physically attachedbut at some other points there is some space between them. In anembodiment, the first high mechanical strength layer and the second highmechanical strength layer are not in physical contact or are not incomplete physical contact. In an embodiment, for example, at least apart of the first high mechanical strength layer and the second highmechanical strength layer are separated by a distance selected from therange of 20 nm to 2 mm. In an embodiment, for example, at least a partof the first high mechanical strength layer or the second highmechanical strength layer is separated from the third high mechanicalstrength layer or the fourth high mechanical strength layer by adistance selected from the range of 20 nm to 2 mm.

In an embodiment, for example, any of, and optionally all of, the firsthigh mechanical strength layer, the second high mechanical strengthlayer, the third high mechanical strength layer, the fourth highmechanical strength layer, the one or more low ionic resistance layers,and the one or more chemical barrier layers independently have anaverage thickness selected over the range of 10 nm to 1 mm, andoptionally for some applications selected over the range of 1 μm to 500μm, and optionally for some applications selected over the range of 10nm to 50 μm. In an embodiment, for example, any of, and optionally allof, the first high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer, the fourthhigh mechanical strength layer, the one or more low ionic resistancelayers, and the one or more chemical barrier layers independently havean average thickness selected over the range 5 μm to 1 mm, optionallyfor some applications selected over the range 25 μm to 5 mm, andoptionally for some applications selected over the range of 100 μm to 2mm, and optionally for some applications selected over the range of 500μm to 1 mm. In an embodiment, for example, any of, and optionally allof, the first high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer, the fourthhigh mechanical strength layer, the one or more low ionic resistancelayers, and the one or more chemical barrier layers independently havean average thickness selected over the range 10 nm to 2 μm or selectedover the range 2 μm to 50 μm.

In an embodiment, for example, any of, and optionally all of, the firsthigh mechanical strength layer, the second high mechanical strengthlayer, the third high mechanical strength layer and the fourth highmechanical strength layer independently have a Young's modulus selectedover the range of 500 MPa to 500 GPa. In an embodiment, for example, anyof, and optionally all of, the first high mechanical strength layer, thesecond high mechanical strength layer, the third high mechanicalstrength layer and the fourth high mechanical strength layerindependently have a yield strength selected over the range of 5 MPa to1000 MPa. In an embodiment, for example, any of, and optionally all of,the first high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer and the fourthhigh mechanical strength layer independently have a propagating tearstrength selected over the range of 0.005 N to 10 N, preferably for someapplications a propagating tear strength more than 0.01 N. In anembodiment, for example, any of, and optionally all of, the first highmechanical strength layer, the second high mechanical strength layer,the third high mechanical strength layer and the fourth high mechanicalstrength layer independently have an initiating tear strength selectedover the range of 10 N to 500 N, preferably for some applications aninitiating tear strength more than 50 N. In an embodiment, for example,any of, and optionally all of, the first high mechanical strength layer,the second high mechanical strength layer, the third high mechanicalstrength layer and the fourth high mechanical strength layerindependently have a tensile strength selected over the range of 50 MPato 2 GPa. In an embodiment, for example, any of, and optionally all of,the first high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer and the fourthhigh mechanical strength layer independently have an impact strengthselected over the range of 10 N cm to 1000 N cm.

In an embodiment, for example, any of, and optionally all of, the firsthigh mechanical strength layer, the second high mechanical strengthlayer, the third high mechanical strength layer and the fourth highmechanical strength layer independently comprise planar layers providedin a parallel configuration. In an embodiment, for example, any of, andoptionally all of, the first high mechanical strength layer, the secondhigh mechanical strength layer, the third high mechanical strength layerand the fourth high mechanical strength layer independently comprisehollow cylindrical layers provided in a concentric configuration. In anembodiment, for example, any of, and optionally all of, the first highmechanical strength layer, the second high mechanical strength layer,the third high mechanical strength layer, the fourth high mechanicalstrength layer, the one or more low ionic resistance layers, and the oneor more chemical barrier layers comprise chemically resistant materials.In an embodiment, the first high mechanical strength layer, the secondhigh mechanical strength layer, the third high mechanical strengthlayer, the fourth high mechanical strength layer, the one or more lowionic resistance layers, and the one or more chemical barrier layers areindependently chemically compatible with an electrolyte it is providedin contact with and/or independently chemically compatible with anelectrode it is provided in contact with.

In an embodiment, for example, any of, and optionally all of, the firsthigh mechanical strength layer, the second high mechanical strengthlayer, the third high mechanical strength layer and the fourth highmechanical strength layer independently comprise a material having amelting point greater than or equal to 100 Celsius. In an embodiment,for example, at least two of the high mechanical strength layers havedifferent melting temperature with the difference of at least 30Celsius, optionally wherein the difference in melting temperatures ofthe high mechanical strength layers provides a shutdown mechanism thatby melting one of the layers the ionic path between two electrodes of anelectrochemical cell closes; or alternatively wherein the difference inmelting temperatures of the high mechanical strength layers result doesnot provide a shutdown mechanism that by melting one of the layers theionic path between two electrodes of an electrochemical cell closes. Inan embodiment, for example, any of, and optionally all of, the firsthigh mechanical strength layer, the second high mechanical strengthlayer, the third high mechanical strength layer and the fourth highmechanical strength layer independently comprise a material having athermal coefficient of thermal expansion is less than or equal to 50ppm/° C.

The first high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer and the fourthhigh mechanical strength layer of separator systems of the invention maycomprise a range of materials selected for a particular application,such as type of electrochemical cell. In an embodiment, for example,first high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer and the fourthhigh mechanical strength layer independently comprise chemicallyresistant materials. In an embodiment, for example, first highmechanical strength layer, the second high mechanical strength layer,the third high mechanical strength layer and the fourth high mechanicalstrength layer independently comprise thermally stable materials. In anembodiment, for example, any of, and optionally all of, the first highmechanical strength layer, the second high mechanical strength layer,the third high mechanical strength layer and the fourth high mechanicalstrength layer independently comprise one or more materials selectedfrom the group consisting of a polymer, a metal, an alloy, a ceramic, awood, a glass, a semiconductor, a woven material, and a nonwovenmaterial. In an embodiment, for example, any of, and optionally all of,the first high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer and the fourthhigh mechanical strength layer independently comprise a material havinga dielectric constant greater than or equal to 50. In an embodiment, forexample, any of, and optionally all of, the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer and the fourth high mechanical strengthlayer independently comprise a conductive material. In an embodiment,for example, any of, and optionally all of, the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer and the fourth high mechanical strengthlayer independently comprise one or more materials selected from thegroup consisting of a gel electrolyte, a solid electrolyte and a polymerelectrolyte. In an embodiment, for example, any of, and optionally allof, the first high mechanical strength layer, the second high mechanicalstrength layer, the third high mechanical strength layer and the fourthhigh mechanical strength layer independently comprise one or morematerials selected from the group consisting of Polyacrylic acid (PAA),Cross-linked polyethylene (PEX, XLPE), Polyethylene (PE), Polyethyleneterephthalate (PET, PETE), Polyphenyl ether (PPE), Polyvinyl chloride(PVC), Polyvinylidene chloride (PVDC), Polylactic acid (PLA),Polypropylene (PP), Polybutylene (PB), Polybutylene terephthalate (PBT),Polyamide (PA), Polyimide (PI), Polycarbonate (PC),Polytetrafluoroethylene (PTFE), Polystyrene (PS), Polyurethane (PU),Polyester (PE), Acrylonitrile butadiene styrene (ABS), Poly(methylmethacrylate) (PMMA), Polyoxymethylene (POM), Polysulfone (PES),Styrene-acrylonitrile (SAN), Ethylene vinyl acetate (EVA), Styrenemaleic anhydride (SMA), PVDF, PEO, LIPON, LISICON, Nafion, ZrO₂,NASICON, tetramethylammonium hydroxide pentahydrate (CH₃)₄NOH.5H₂O,poly(ethylene oxide) (PEO), copolymer of epichlorohydrin and ethyleneoxide P(ECH-co-EO) and poly(vinylalcohol), PEO-PVA-glassfibre polymerelectrolyte, zinc sulfide, silicon dioxide, PVA and PSA, PVA/V6/PSS;PVAN6/(PSS+PAA); V6/PVA/(PSS+PAA); PVMPSS+PAA (35%))/(PSS+PAA (35%));(PSS+PAA (35%))/PVA/(PSS+PAA (35%)); or (PSS+PAA (35%))/(PVA (10%)+PSS(20% VS. PVA))/(PSS+PAA (35%)) polyethylene glycol, polypropyleneglycol, polybutylene glycol, alkyl-polyethylene glycol,alkyl-polypropylene glycol, alkyl-polybutylene glycol, a copolymerthereof, a PEO material or a PVA material and any combination thereof.

In an embodiment, for example, a surface of any of the first highmechanical strength layer, the second high mechanical strength layer,the third high mechanical strength layer and the fourth high mechanicalstrength layer is wet-able with an electrolyte. In an embodiment, forexample, a surface of any of the first high mechanical strength layer,the second high mechanical strength layer, the third high mechanicalstrength layer and the fourth high mechanical strength layer is coatedwith a coating that is wet-able with an electrolyte. In an embodiment,for example, at least a portion of a surface of any of the first highmechanical strength layer, the second high mechanical strength layer,the third high mechanical strength layer and the fourth high mechanicalstrength layer is coated with an adhesive coating, optionally coveringless than 10% of the surface. In an embodiment, for example, at least aportion of a surface of any of the first high mechanical strength layer,the second high mechanical strength layer, the third high mechanicalstrength layer and the fourth high mechanical strength layer is coatedwith an adhesive coating having a thickness less than 5 μm. In anembodiment, for example, at least one surface of any of the first highmechanical strength layer, the second high mechanical strength layer,the third high mechanical strength layer and the fourth high mechanicalstrength layer has a surface roughness, such as a surface roughnesscharacterized by a rms (root mean square) selected from the range of 1nm to 1000 nm, providing a space for an electrolyte between at least aportion of the first high mechanical strength layer, the second highmechanical strength layer, the third high mechanical strength layer orthe fourth high mechanical strength layer. In an embodiment, forexample, the separator system is a component in an electrochemical cellhaving a positive electrode and a negative electrode; wherein at leastone surface of any of the first high mechanical strength layer, thesecond high mechanical strength layer, the third high mechanicalstrength layer and the fourth high mechanical strength layer has asurface roughness such as a surface roughness characterized by a rmsselected from the range of 1 nm to 1000 nm, providing a space for anelectrolyte between the first high mechanical strength layer, the secondhigh mechanical strength layer, the third high mechanical strength layeror the fourth high mechanical strength layer and the positive electrodeor the negative electrode of the electrochemical cell. In an embodiment,for example, the surface roughness provides a distance between at leasta portion of two of the high mechanical strength layers or between atleast a portion of a high mechanical strength layer and the positiveelectrode or negative electrode selected from the range of 5 nm and 5micrometers.

In an aspect, the invention provides a separator system wherein at leastsome of the first high mechanical strength layer, the second highmechanical strength layer, the third high mechanical strength layer, thefourth high mechanical strength layer, low ionic resistance layers,frame layers, spacer, chemical barrier layers, or any combination ofthese have a high surface energy, preferably for some applications asurface energy greater than or equal to 10 mJ/m². In an embodiment, forexample, the surface energy of any of these components facilitates thewettability of the layers with the electrolyte. In an embodiment, forexample, the surface energy of any of these components helps with theattachment of the layers to each other or to the electrodes of anelectrochemical cell.

In an aspect, the separator further comprises one or more coatingsprovided on any of the first high mechanical strength layer, the secondhigh mechanical strength layer, the third high mechanical strength layerand the fourth high mechanical strength layer. In an embodiment, forexample, the one or more coatings independently comprises one or morenon-conductive coatings. In an embodiment, for example, the one or morecoatings independently comprises one or more hydrophobic coatings and/orhydrophilic coatings. In an embodiment, for example, the one or morecoatings independently comprises polyethylene glycol. In an embodiment,for example, the one or more coatings prevent material transport from apositive electrode to a negative electrode of an electrochemical cell.In an embodiment, for example, the one or more coatings independentlyhave a thickness selected from the range of 10 nm to 2 μm. In anembodiment, for example, the separator is for an electrochemical cellhaving a sulfur-based cathode, wherein the one or more coating repelshydrophobic polysulfides and increases the performance and cycle life ofthe electrochemical cell. In an embodiment, the hydroponic orhydrophobic coating is provided for a sulfur based cathode Li-battery. Aproblem with state of the art for a sulfur based cathode Li-batteries isthat the electrochemical reactions are solvable in the electrolyte and,thus there may be a significant capacity loss due to the passage of thematerials (inter-medially poly sulfides) from the sulfur electrode tothe Li electrode through the electrolyte. To prevent this problem, aseparator of a specific embodiment is coated with polyethylene glycolmaterial (hydrophilic) which repels the hydrophobic poly sulfides and,thus hinders the materials passage and capacity loss. Use of a coatingin embodiments of the invention is also useful in protecting a Li anodefrom moisture, say a by a hydrophobic coating on the separator, forexample in a lithium-air and lithium water electrochemical cell.

In an embodiment, for example, any of the first high mechanical strengthlayer, the second high mechanical strength layer, the third highmechanical strength layer and the fourth high mechanical strength layeris independently a metal layer, optionally selected from the groupconsisting of Al, Ni, Cu and stainless steel. In an embodiment, forexample, the coating is a non-conductive coating, optionally comprisingPTFE, PE, PP, PVC, or a polyimide.

The invention includes separator systems useful for with a range ofelectrochemical systems. In an embodiment, for example, the inventionprovides a separator system for a primary electrochemical cell orsecondary electrochemical cell. In an embodiment, for example, theinvention provides a separator system for a lithium battery, an alkalinebattery, zinc battery or a lead acid battery. In an embodiment, forexample, the invention provides a separator system for a lithiummetal-air battery, a lithium ion battery, a lithium air battery, aFe-air battery, an Al-air battery, or a zinc-air battery. In anembodiment, for example, the invention provides a separator system for afuel cell, a flow battery system, a semisolid battery, a 3-D battery, anano-battery, a micro-battery or an electrochemical capacitor.

In another aspect, the invention provides an electrochemical cellcomprising: (i) a negative electrode; (ii) a positive electrode; (iii) afirst electrolyte provided between the positive electrode and thenegative electrode; and (iv) a separator system of the inventionprovided in contact with the electrolyte and between the negativeelectrode and the positive electrode; wherein the separator system ispositioned such that ions of the electrolyte are able to be transportedbetween the positive electrode and the negative electrode. In an aspect,the separator system prevents electrical contact between the positiveelectrode and the negative electrode. As will be understood by one ofskill in the art, any of the separator systems described herein can beused for electrochemical systems of the invention, such aselectrochemical cells.

In an embodiment, for example, the separator system is provided inphysical contact with the positive electrode and the negative electrode.In an embodiment, for example, the separator system provides an ionicconductivity between the positive electrode and the negative electrodeequal to or greater than 1×10⁻³ S/cm, optionally for some applicationspreferably greater than 1×10⁻² S/cm. In an embodiment, for example, theseparator system provides a net ionic resistance from the positiveelectrode to the negative electrode selected over the range of 0.5 ohmcm² to 25 ohm cm², and preferably for some applications less than 5 ohmcm².

In an embodiment, the electrochemical cell further comprises a chemicalbarrier layer provided between the positive electrode and the negativeelectrode; the electrochemical cell further comprising a secondelectrolyte provided between the positive electrode and the negativeelectrode, wherein the chemical barrier layer prevents mixing of thefirst electrolyte and the second electrolyte.

In an embodiment, for example, the off-set alignment of the highmechanical strength layers provides no direct, linear path between thepositive and negative electrodes. In an embodiment, for example, theoff-set alignment prevents shorting via electrical contact between thepositive electrode and the negative electrode by manufacturing defects,external objects or the formation of dendrites on the positive electrodeor negative electrode. Embodiments of this aspect are beneficial, forexample, for minimizing or preventing electrical shorting from thepositive electrode to the negative electrode or thermal runaway issuesarising from the formation of dendrites. Embodiments of this aspect arebeneficial, for example, for providing electrochemical cells capable ofenhanced cycling and/or high discharge rate performance.

In an embodiment, for example, at least one of the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer, the fourth high mechanical strengthlayer, the low ionic resistance layers, the frame layers, the spacer,the chemical barrier layers, or any combination of these are at leastpartially attached the positive electrode or the negative electrode byvia pressure, heating, an adhesive coating, a chemical adherent, plasmatreating or by depositing or coating one layer on another layer or on anelectrode or any combination of these. In an embodiment, for example, atleast one of the first high mechanical strength layer, the second highmechanical strength layer, the third high mechanical strength layer, thefourth high mechanical strength layer, the low ionic resistance layers,the frame layers, the spacer, the chemical barrier layers, or anycombination of these are at least partially attached to the positiveelectrode or the negative electrode by via a glue, epoxy, cement, aTelfon coating, a solid electrolyte, a gel electrolyte or a polymerelectrolyte. In an embodiment, for example, at least one of the firsthigh mechanical strength layer, the second high mechanical strengthlayer, the third high mechanical strength layer, the fourth highmechanical strength layer, low ionic resistance layers, frame layers,spacer, chemical barrier layers, or any combination of these comprise acoating deposited on a surface of the positive electrode or the negativeelectrode.

In an embodiment, for example, the invention provides an electrochemicalcell incorporating the present separator system having a cycle capacityat least 300 cycles, and preferably for some applications at least 500cycles. In an embodiment, for example, the invention provides anelectrochemical cell incorporating the present separator system having aspecific capacity equal to or greater than 100 mAh g⁻¹ at a dischargerate equal to or greater than C/5. In an embodiment, for example, theinvention provides an electrochemical cell having

Electrochemical cells and separator systems of the invention arecompatible with a range of electrolytes, including liquid electrolytes,solid, electrolytes, gel electrolytes, aprotic electrolytes, aqueouselectrolytes and nonaqueous electrolytes. In an embodiment, for example,the electrolyte comprises a solid charge carrying media or a gelelectrode. In an embodiment, for example, the electrolyte comprises apolymeric media. In an embodiment, for example, the electrolytecomprises polyethylene oxide, polytetrafluoroethylene, polyvinylidenefluoride, fluorine-containing copolymers, polyacrylonitrile, and anycombinations thereof.

In an embodiment, for example, the electrolyte comprises an alkali metalsalt at least partially dissolved in one or more nonaqueous solvents. Inan embodiment, for example, the electrolyte comprises a solvent and asupporting salt; wherein the solvent is selected from the groupconsisting of organic carbonates, ethers, esters, formates, lactones,sulfones, sulfolane, 1,3-dioxolane, ethylene carbonate, propylenecarbonate, dimethyl carbonate, diethyl carbonate, ethyl methylcarbonate, butylene carbonate, vinylene carbonate, fluoroethylenecarbonate, fluoropropylene carbonate, y-butylrolactone, methyldifluoroacetate, ethyl difluoroacetate, dimethoxyethane, diglyme(bis(2-methoxyethyl)ether), tetrahydrofuran, dioxolane, 2MeTHF, 1,2-DMEor higher glymes, sulfolane, methyl formate, methyl acetate, and anycombinations thereof; and wherein the supporting salt is selected fromthe group consisting of LiPF₆, LiBF₄, LiAsF₆, LiClO₄, LiSO₃CF₃,LiN(CF₃SO₂)₂, LiN(SO₂C₂F₅)₂ an any combinations thereof. In anembodiment, for example, the electrolyte comprises a golfing agentselected from the group consisting of PVdF, PVdF-HFP copolymer, PAN, andPEO and mixtures thereof; a plasticizer selected from the groupconsisting of EC, PC, DEC, DMC, EMC, THE, 2MeTHF, 1,2-DME and mixturesthereof; and a Li salt selected from the group consisting of LiPF6,LiBF₄, LiAsF₆, LiClO₄, LiSO₃CF₃, LiN(CF₃SO₂)₂ and LiN(SO₂C₂F5)₂.

In an aspect, the invention provides an electrochemical cell having afirst electrolyte on a first side of the cell including the positiveelectrode and a second electrolyte on a second side of the cellincluding the negative electrode, wherein the first electrolyte has adifferent composition than the second electrolyte, and wherein theelectrochemical cell further comprises one or more chemical barrierlayers comprising an ion conductive protective membrane positionedbetween the positive electrode and the negative electrode. In anembodiment of this aspect, the first electrolyte is an aqueouselectrolyte and the second electrolyte is an aprotic electrolyte. In anembodiment of this aspect, at least one of the first electrolyte and thesecond electrolyte is a solid electrolyte.

Electrochemical cells and separator systems of the invention arecompatible with electrodes having a range of compositions, form factorsand device geometries. In an embodiment, for example, the negativeelectrode, the positive electrode or both comprise a micro-sizedmaterial of a nano-sized material. As used herein, nano-sized refers toa structure, such as a particle or thin film, having at least onephysical dimension (e.g., length, height, width, diameter, etc.) that isselected over the range of 1 nm to 1000 nm. As used herein, micro-sizedrefers to a structure, such as a particle or thin film, having at leastone physical dimension (e.g., length, height, width, diameter, etc.)that is selected over the range of 1 μm to 1000 μm. In an embodiment,for example, the negative electrode or the positive electrode is in theform of a powder, such as a mixture of active electrode particles andconductive particles. In an embodiment, for example, the negativeelectrode or the positive electrode is in the form of a thin film. In anembodiment, for example, the invention provides an electrochemical cellwherein at least one of the positive electrode or negative electrode inthe form of a solvated metal, such as solvated lithium or a solvatedlithium alloy. In an embodiment, for example, the invention provides anelectrochemical cell wherein at least one of the positive electrode ornegative electrode in the form of a molten metal.

In an embodiment, for example, the invention provides an electrochemicalcell wherein the negative electrode comprises a material selected fromthe group consisting of lithium, zinc, aluminum, silicon, tin, antimony,lead, germanium, magnesium, cadmium, bismuth, indium, molybdenum,niobium, tungsten, tantalum, iron, nickel, manganese, copper, a sodiumtransition metal phosphate, a sodium mixed metal phosphate;Li₄/3Ti5/3O₄, graphite, an alloy of tin, cobalt, carbon, LiVO₂,Li₄Ti₅O₁₂, Li4/3Ti5/3O₄ TiO₂, WO₂, and MoO₂. In an embodiment, forexample, the invention provides an electrochemical cell wherein thepositive electrode comprises a material selected from the groupconsisting of graphite, LiCoO_2NiO_8O₂, LiNiO2, LiFePO₄, LiMnPO₄,LiCoPO₄, LiMn₂O₄, LiCoO₂, LiNiO_5Mn I.5O₄, LiVPO₄ F, silver oxide,nickel oxide, cobalt oxide, manganese oxide, AgO, Ag₂O₃, Zn, ZnO AgO,Ag₂O, Ag₂O₃, HgO, Hg₂O, CuO, CdO, NiOOH, Pb₂O₄, PbO₂, LiFePO₄,Li₃V₂(PO₄)₃, V₆O₁₃, V₂O₅, Fe₃O₄, Fe₂O₃, MnO₂, LiCoO₂, LiNiO₂, LiMn₂O₄,LiVO₂, Li₄Ti₅O₁₂, TiO₂, WO₂, and MoO₂. In an embodiment, for example,the invention provides an electrochemical cell wherein the positiveelectrode comprises a material selected from the group consisting of a(i) lithiated metal oxide based cathode selected from the groupconsisting of LixCoO₂, Li_(x)NiO₂, LixMn₂O₄ and LiFePO₄; (ii) anunlithiated metal oxide based cathode selected from the group consistingof Ag_(x)V₂O₅, Cu_(x)V₂O₅, V₂O₅, V₆O₁₃, MnO₂, CuO, Ag₂CrO₄ and MoO₃,wherein x ranges from 0 to 2; (iii) a lithiated metal oxide basedcathode selected from the group consisting of FeS₂, TiS₂, FeS and CuS;(iv) an active sulfur cathode selected from the group consisting ofelemental sulfur, polysulfides and combinations thereof; and (v) aPEO/carbon/metal-oxide type cathode structure comprising an aqueouselectrochemically active component such as water or a water solubleoxidant selected from the group consisting of gaseous, liquid and solidoxidants and combinations thereof such as peroxide, hydrogen peroxide,O₂, SO₂ and NO₂, and the water soluble solid oxidants are selected fromthe group consisting of NaNO₂, KNO₂, Na₂SO₃ and K₂SO₃ wherein thecathode structure electronically conductive component is a porouscatalytic support such as nickel and wherein the cathode structureelectrochemically active material comprises air.

Electrochemical cells of the invention include primary electrochemicalcells and secondary electrochemical cells. In an embodiment, forexample, the invention provides an electrochemical cell comprising alithium battery, an alkaline battery, zinc battery, a lead acid battery,a lithium metal-air battery, a lithium ion battery, a lithium airbattery, a Fe-air battery, a Al-air battery, or a zinc-air battery. Inan embodiment, for example, the invention provides an electrochemicalcell comprising a fuel cell, a flow battery system, a semisolid battery,a 3-D battery, a nano-battery, a micro-battery, or an electrochemicalcapacitor. In an embodiment, for example, the invention provides anelectrochemical cell comprising a thin film battery. In an embodiment,for example, the invention provides an electrochemical cell that is analkaline metal ion battery.

In an embodiment, for example, the invention provides a battery packcomprising one or more electrochemical cells, such as one or morelithium ion electrochemical cells. As will be understood by one of skillin the art, any of the separator systems and electrochemical cellsdescribed herein can be used for alkali metal flow batteries,supercapacitors or fuel cells of the invention.

In an aspect, the invention provides an alkali metal fuel cell,comprising: (i) a renewable anode comprising solid alkali metal andalkali metal dissolved in a solvent as fuel; (ii) a cathode structurecomprising a static electronically conductive component, an ionicallyconductive component comprising an electrolyte for ions of the alkalimetal, and a fluid oxidant obtained from an operating environment of thecell; and (iii) a separator system of the invention provided between theanode and cathode structure. As will be understood by one of skill inthe art, any of the separator systems described herein can be used foralkali metal flow batteries, supercapacitors or fuel cells of theinvention.

In an aspect, the invention provides a method of making anelectrochemical cell, the method comprising the steps of: (i) providinga negative electrode; (ii) providing a positive electrode; (iii)providing an electrolyte between the positive electrode and the negativeelectrode; and (iv) providing a separator system positioned between thepositive electrode and the negative electrode, wherein the separatorsystem comprises (i) a first high mechanical strength layer having aplurality of apertures extending entirely through the first highmechanical strength layer and provided in a first pattern; and (ii) asecond high mechanical strength layer having a plurality of aperturesextending entirely through the second high mechanical strength layer andprovided in a second pattern; the second pattern having an off-setalignment relative to the first pattern such that an overlap of theapertures of the first high mechanical strength layer and the aperturesof the second high mechanical strength layer along axes extendingperpendicularly from the first high mechanical strength layer to thesecond high mechanical strength layer is less than or equal to 20%;wherein the first high mechanical strength layer and the second highmechanical strength layer are positioned such that ions of anelectrolyte provided in contact with the first high mechanical strengthlayer and the second high mechanical strength layer are able to betransported through the first high mechanical strength layer and thesecond high mechanical strength layer. In an embodiment, the separatorsystem is at least partially in physical contact with the electrolyte.In an embodiment, the method further comprises providing an ionconductive chemical barrier between the positive electrode and thenegative electrode; wherein the ion conductive chemical barrierseparates a first electrolyte in contact with the positive electrodefrom a second electrolyte that is in connect with the negativeelectrode; wherein the first electrolyte has a different compositionfrom the second electrolyte; and wherein the ion conductive chemicalbarrier prevents mixing of the first electrolyte and the secondelectrolyte. As will be generally understood by one of skill in the art,any of the present separator systems and systems of the invention,including all specific embodiments and combinations of components,materials and properties described herein, may be used in the presentmethods of making an electrochemical cell.

In an aspect, the invention provides a method of generating anelectrical current, the method comprising the steps of: (i) providing anelectrochemical cell, wherein the electrochemical cell comprises: (1) afirst high mechanical strength layer having a plurality of aperturesextending entirely through the first high mechanical strength layer andprovided in a first pattern; and (2) a second high mechanical strengthlayer having a plurality of apertures extending entirely through thesecond high mechanical strength layer and provided in a second pattern;the second pattern having an off-set alignment relative to the firstpattern such that an overlap of the apertures of the first highmechanical strength layer and the apertures of the second highmechanical strength layer along axes extending perpendicularly from thefirst high mechanical strength layer to the second high mechanicalstrength layer is less than or equal to 20%; wherein the first highmechanical strength layer and the second high mechanical strength layerare positioned such that ions of an electrolyte provided in contact withthe first high mechanical strength layer and the second high mechanicalstrength layer are able to be transported through the first highmechanical strength layer and the second high mechanical strength layer;and (ii) discharging the electrochemical cell. In an embodiment, themethod of this aspect further includes the step of charging theelectrochemical cell. In an embodiment, the method of this aspectfurther includes the step of cycling the electrochemical cell through aplurality of charge and discharge cycles. As will be generallyunderstood by one of skill in the art, any of the present separatorsystems and systems of the invention, including all specific embodimentsand combinations of components, materials and properties describedherein, may be used in the present methods of generating an electricalcurrent.

In another aspect, provided are electrochemical cells comprising: apositive electrode; a negative electrode; an ionically conductive andelectronically insulating separator positioned between the positiveelectrode and the negative electrode; a first electronically andionically conductive layer positioned between the positive electrode andthe separator and in electrical contact with the positive electrode orpositioned between the negative electrode and the separator and inelectrical contact with the negative electrode; and one or moreelectrolytes positioned between the positive electrode and the negativeelectrode; wherein the one or more electrolytes are capable ofconducting charge carriers.

Optionally the first electronically and ionically conductive layercomprises a metal, a metal alloy, a carbon material, a semiconductor, anelectronically conductive polymer, an electronically conductive ceramicor any combination of these. Optionally, the first electronically andionically conductive layer comprises a metallic or alloy mesh, ametallic or alloy perforated layer, a metal or alloy coating, a carboncoating, a porous layer, a perforated layer, a mesh, a foam, an at leastpartial coating of a conductive material or any combination of these.Optionally, the first electronically and ionically conductive layercomprises a Au, Al, Cu, Ti, Zn, Ag, stainless steel, Li, Sn, Si, Ni,steel, Tungsten, Tin, Lead, Constantan, Mercury, Germanium or any oftheir alloys, graphite, carbon black, graphene, carbon nanotubes, coke,Li alloys, Fe alloys, Indium tin oxide (ITO), lanthanum-doped strontiumtitanate (SLT), yttrium-doped strontium titanate (SYT), Poly(fluorene)s,polyphenylenes, polypyrenes, polyazulenes, polynaphthalenes,Poly(acetylene)s, Poly(p-phenylene vinylene), poly(pyrrole)s,polycarbazoles, polyindoles, polyazepines, polyanilines,poly(thiophene)s, poly(3,4-ethylenedioxythiophene), poly(p-phenylenesulfide), polyfluorene-based conducting polymers, PAN,Poly(9,9-dioctylfluorene-co-fluorenone,Poly(9,9-dioctylefluorene-co-fluorenone-co-methylbenzoic ester),polythiophene, polypyrrole, poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT:PSS), [(ferocenyl)amidopropyl]pyrrole,pyrrole, polypyrrole, polyaniline, polythiophene, polyfuran, SiO₂,Napon, PVC or their doped compositions or their mixtures; or anycombination of these.

Optionally, the first electronically and ionically conductive layercomprises a porous or perforated material having a porosity greater thanor equal to 30%, greater than or equal to 40%, greater than or equal to50%, greater than or equal to 60%, greater than or equal to 70%, greaterthan or equal to 80%, greater than or equal to 90%, selected from therange of 30% to 90%, selected from the range of 40% to 80%, selectedfrom the range of 50% to 70% or selected from the range of 50% to 90%.

Optionally, the first electronically and ionically conductive layercomprises a chemically resistant material, a heat resistant material, amechanically resistant material or any combination of these. Optionally,the first electronically and ionically conductive layer comprises a thinfilm structure deposited on at least one external surface of theseparator, the positive electrode or the negative electrode. Optionally,the first electronically and ionically conductive layer comprises acoating coated on at least one external surface of the separator, thepositive electrode or the negative electrode.

Optionally, the first electronically and ionically conductive layer hasan electronical conductivity greater than or equal to 1 S/cm, greaterthan or equal to 10 S/cm or greater than or equal to 100 S/cm.Optionally, the first electronically and ionically conductive layer hasan ionic resistance less than or equal to 10 Ω·cm², less than or equalto 5 Ω·cm², less than or equal to 3 Ω·cm², less than or equal to 1Ω·cm², selected from the range of 0.3 Ω·cm² to 3 Ω·cm², selected fromthe range of 0.03 Ω·cm² to 3 Ω·cm², selected from the range of 0.1 Ω·cm²to 10 Ω·cm², selected from the range of 0.3 Ω·cm² to 5 Ω·cm² or selectedfrom the range of 0.3 Ω·cm² to 3 Ω·cm².

Optionally, the first electronically and ionically conductive layer hasa thickness less than or equal to 100 μm, less than or equal to 50 μm,less than or equal to 25 μm, less than or equal to 10 μm, less than orequal to 1 μm, less than or equal to 100 nm, selected from the range of10 nm to 100 μm, selected from the range of 10 nm to 10 μm or, selectedfrom the range of 50 nm to 5 μm.

Optionally, the first electronically and ionically conductive layer isprovided in physical contact with the separator. Optionally, the firstelectronically and ionically conductive layer is in physical contactwith at least 10% of an exterior surface of the separator. Optionally,the first electronically and ionically conductive layer is in physicalcontact with the positive electrode or the negative electrode.Optionally, the first electronically and ionically conductive layer isin physical contact with at least 10% of an exterior surface of thepositive electrode or the negative electrode. Optionally, the firstelectronically and ionically conductive layer is at least partiallycovered with the positive electrode material or the negative electrodematerial.

In embodiments, the first electronically and ionically conductive layerincreases an electronic conductivity of at least a portion of thenegative electrode or the positive electrode. Optionally, the firstelectronically and ionically conductive layer provides an added path forelectron transfer between the positive electrode and a positiveelectrode current collector, an added path for electron transfer betweenthe negative electrode and a negative electrode current collector, ahomogeneous electric field adjacent to and within the positive electrodeor a homogeneous electric field adjacent to and within the negativeelectrode or any combination of these provided benefits. Optionally, thefirst electronically and ionically conductive layer provides anauxiliary path for electrons to or from the positive electrode or thenegative electrode. Optionally, the first electronically and ionicallyconductive layer provides a homogeneous electric field adjacent to andwithin the positive electrode or the negative electrode, therebyproviding uniform ion deposition into the positive electrode or thenegative electrode. In exemplary embodiments, the first electronicallyand ionically conductive layer prevents dendrite growth on or from thepositive electrode or the negative electrode.

In certain embodiments, an electrochemical cell of this aspect furthercomprises a second electronically and ionically conductive layer.Optionally, the first electronically and ionically conductive layer ispositioned in electrical contact with the positive electrode and whereinthe second electronically and ionically conductive layer is positionedin electrical contact with the negative electrode.

Optionally, the separator comprises a microporous layer comprising apolymer, polyethylene, polypropylene, polyethylene terephthalate,Kapton, polyester, Nafion, ZrO₂, polyimide, polytetrofluoroethylene,glass separator, nonwoven separator, woven separator or any combinationof these. Optionally, the separator comprises a polymer electrolyte, asolid electrolyte, a gel electrolyte, Nafion, ZrO₂, PVDF, PEO, PMMA,LISICON, NASICON, LIPON, NaPON, PE, PP, PET, Kapton or any combinationof these.

In embodiments, the separator comprises a high mechanical strengthlayer. Optionally, the separator comprises a first high mechanicalstrength layer having a plurality of apertures extending entirelythrough the first high mechanical strength layer and provided in a firstpattern. Optionally, the separator further comprises a first ionicallyconductive and electronically insulating material provided in at least aportion of the plurality of apertures of the first high mechanicalstrength layer.

In some embodiments, for example, the separator comprises: a first highmechanical strength layer having a plurality of apertures extendingentirely through the first high mechanical strength layer and providedin a first pattern; and a second high mechanical strength layer having aplurality of apertures extending entirely through the second highmechanical strength layer and provided in a second pattern; the secondpattern having an off-set alignment relative to the first pattern suchthat an overlap of the apertures of the first high mechanical strengthlayer and the apertures of the second high mechanical strength layeralong axes extending perpendicularly from the first high mechanicalstrength layer to the second high mechanical strength layer is less thanor equal to 20%; wherein the first high mechanical strength layer andthe second high mechanical strength layer are positioned such that ionsof an electrolyte provided in contact with the first high mechanicalstrength layer and the second high mechanical strength layer are able tobe transported through the first high mechanical strength layer and thesecond high mechanical strength layer.

Optionally, the separator comprises a coating coated on at least oneexternal surface of the first electronically and ionically conductivelayer, at least one surface of the positive electrode or at least onesurface of the negative electrode. Optionally, the separator comprises athin film deposited on at least one external surface of the firstelectronically and ionically conductive layer, at least one surface ofthe positive electrode or at least one surface of the negativeelectrode. Optionally, the first electronically and ionically conductivelayer is a component of the separator. Optionally, the firstelectronically and ionically conductive layer is a coating on theseparator. Optionally the separator has a total thickness less than orequal to 500 μm or selected or the range of 10 nm to 200 μm.

Optionally, the positive electrode or negative electrode comprises anintercalation host material. Optionally, the positive electrode ornegative electrode comprises a material that undergoes a change in shapeduring charging or discharging of the electrochemical cell. Optionally,the positive electrode comprises a metal oxide, sulfur, SO₂,Lithium-thionyl chloride, MnO₂, CF_(x), CuO, V₆O₁₃, V₂O₅, FeS₂, CuCl₂,I₂, HgO, Cadmium, bromine, hydrogen based electrode, oxygen basedelectrode, bromine, FeS, V₂O₅, Ag, Ni, Pb, PbO₂, Carbon, LiCoO₂, LiFePO₄LiMn₂O₄, carbon based oxygen cathode, carbon based water cathode, analkali metal, an alkali metal alloy, a binary or ternary alkali metalalloy with or more of Ca, Mg, Sn, Ag, Zn, Bi, Al, Cd, Ga, In, zincoxide, Na, lead oxide, Li, Lithium oxide, Lithium peroxide, lithiumtitanium oxide, oxygen active material cathode, water active materialcathode, Na_(2/3)[Fe_(1/2)Mn_(1/2)]O₂, copper hexacyanoferrate,polypyrrole, activated carbon, grapheme, graphite, nanocarbon, antimony,a tin and antimony alloy, 5% vanadium-doped lithium iron phosphate,lithium iron fluorophosphates, manganese spinel, lithium nickelmanganese cobalt, purpurin, lithium purpurin, lithium vanadium oxide,lithium titanate, cobalt oxide, iron phosphate, titanium dioxide,silicon, copper antinomide, a water soluble gaseous oxidant, a watersoluble liquid oxidant, a water soluble solid oxidant or any combinationof these. Optionally, the negative electrode comprises Si, Li, Zn, ZnO,Carbon, Na, Mg, Sn, Cd, Pb, PbO₂, LTO, vanadium oxide, an alkali metal,an alkali metal alloy, a binary or ternary alkali metal alloy with ormore of Ca, Mg, Sn, Ag, Zn, Bi, Al, Cd, Ga, In, zinc oxide, Na, leadoxide, Li, Lithium oxide, Lithium peroxide, lithium titanium oxide,oxygen active material cathode, water active material cathode,Na_(2/3)[Fe_(1/2)Mn_(1/2)]O₂, copper hexacyanoferrate, polypyrrole,activated carbon, grapheme, graphite, nanocarbon, antimony, a tin andantimony alloy, 5% vanadium-doped lithium iron phosphate, lithium ironfluorophosphates, manganese spinel, lithium nickel manganese cobalt,purpurin, lithium purpurin, lithium vanadium oxide, lithium titanate,cobalt oxide, iron phosphate, titanium dioxide, silicon, SO₂,Lithium-thionyl chloride, MnO₂, CF_(x), CuO, V₆O₁₃, V₂O₅, FeS₂, CuCl₂,I₂, HgO, Cadmium, bromine, hydrogen based electrode, oxygen basedelectrode, bromine, copper antinomide; or any combination of these.

Optionally, the positive electrode comprises an active positiveelectrode material; and wherein the first electronically and ionicallyconductive layer is provided in electrical contact with the activepositive electrode material. Optionally, the positive electrode furthercomprises a current collector in electrical contact with the activepositive electrode material. Optionally, the negative electrodecomprises an active negative electrode material; and wherein the firstelectronically and ionically conductive layer is provided in electricalcontact with the active negative electrode material. Optionally, thenegative electrode further comprises a current collector in electricalcontact with the active negative electrode material.

Optionally, an electronically and ionically conductive layer comprisesan external current collector pole, for example for use in reductionand/or oxidation. Optionally the first electronically and ionicallyconductive layer reduces one of the positive electrode and the negativeelectrode. Optionally, the external current collector pole oxidizes oneof the positive electrode and the negative electrode, such as occurs inoxygen evolution in a metal-air battery.

In various embodiments, wherein the electrochemical cell comprises asecondary battery, a primary battery, a flow battery, a fuel cell or asemi-solid battery or or an electrochemical capacitor or a lead acidbattery. Optionally, the electrochemical cell comprises a lithium ionbattery, a lithium metal battery, a zinc battery, a lithium-air battery,a zinc-air battery, an aluminum-air battery, an iron-air battery, alithium-water battery, a silicon based battery, a sodium battery, amagnesium battery, a sodium ion battery, a magnesium ion battery, analkaline battery or a lead acid battery or a redox flow battery or afuel cell or an electrochemical capacitor. Optionally, theelectrochemical cell comprises a lithium battery comprising one or moreof a silicon based anode, a lithium anode, a metal oxide electrode, asulfur based cathode, a carbon-based oxygen cathode and a carbon basedwater cathode.

In another aspect, provided are electrochemical cells comprising: apositive electrode; a negative electrode; an ionically conductive andelectronically insulating separator positioned between the positiveelectrode and the negative electrode, wherein the separator comprises: afirst high mechanical strength layer having a plurality of aperturesextending entirely through the first high mechanical strength layer andprovided in a first pattern; and a first ionically conductive andelectronically insulating material provided in at least a portion of theplurality of apertures of the first high mechanical strength layer; afirst electrolyte positioned between the positive electrode and theseparator; and a second electrolyte positioned between the negativeelectrode and the separator; wherein the first and second electrolytesare capable of conducting charge carriers.

Optionally, the first ionically conductive and electronically insulatingmaterial comprises a solid electrolyte, a gel electrolyte, a polymerelectrolyte, Nafion, ZrO₂, LISICON, NASICON, PEO, Li₁₀GeP₂S₁₂, LIPON,PVDF, Li₃N, Li₃P, LiI, LiBr, LiCl, LiF, lithium imide, KOH, NaOH, oxideperovskite, La_(0.5), Li_(0.5)TiO₃, thio-LISICON,Li_(3.25)Ge_(0.25)P_(0.75)S₄, glass ceramics, Li₇P₃S₁₁, glassymaterials, Li₂S—SiS₂—Li₃PO₄, lithium nitride, polyethylene oxide, DopedLi₃N, Li₂S—SiS₂—Li₃PO₄, LIPON, Li₁₄Zn(GeO₄)₄, Li-beta-alumina,Li_(3.6)Si_(0.6)P_(0.4)O₄, Li₂S—P₂S₅, PEO-LiClO₄,LiN(CF₃SO₂)₂/(CH₂CH₂O)₈, NaPON, SiO₂, alumina, silica glass, ceramics,glass-ceramics, water-stable polymers, glassy metal ion conductors,amorphous metal ion conductors, ceramic active metal ion conductors,glass-ceramic active metal ion conductors, an ion conducting ceramic, anion conducting solid solution, an ion conducting glass, a solid lithiumion conductor or any combination of these.

Optionally, the first ionically conductive and electronically insulatingmaterial comprises 10% or more, 20% or more, 30% or more, 40% or more,50% or more, 60% or more, 70% or more or 80% or more by volume of theseparator. Optionally, the first ionically conductive and electronicallyinsulating material comprises 10% or more, 20% or more, 30% or more, 40%or more, 50% or more, 60% or more, 70% or more or 80% or more of asurface area of the separator.

Optionally, the first ionically conductive and electronically insulatingmaterial has an average thickness selected from the range 0.01 μm to2000 μm. Optionally, the first ionically conductive and electronicallyinsulating material has an average thickness selected from the range0.005 mm to 0.05 mm.

In embodiments, the first ionically conductive and electronicallyinsulating material has an average porosity less than 1% or isnon-porous. Optionally, the first ionically conductive andelectronically insulating material has an average porosity selected fromthe range of 0% to 5%. Preferably, first ionically conductive andelectronically insulating material is substantially free of pinholes,cracks, holes or any combination of these. Preferably, the firstionically conductive and electronically insulating material issubstantially free of defects. Optionally, the first ionicallyconductive and electronically insulating material is doped.

Optionally, the first ionically conductive and electronically insulatingmaterial has an ionic conductivity greater than or equal to 10⁻⁵ S/cm,greater than or equal to 10⁻⁴ S/cm, greater than or equal to 10⁻⁴ S/cm,greater than or equal to 10⁻³ S/cm, greater than or equal to 10⁻² S/cm,greater than or equal to 10⁻¹ S/cm, greater than or equal to 10 S/cm,selected from the range of 10⁻⁷S/cm to 100 S/cm, selected from the rangeof 10⁻⁵ S/cm to 10 S/cm, selected from the range of 10⁻³ S/cm to 1 S/cm.Optionally, the first ionically conductive and electronically insulatingmaterial has an ionic conductivity selected from the range of 10⁻⁷S/cmto 100 S/cm at an operating temperature of the cell.

Optionally, the first ionically conductive and electronically insulatingmaterial is provided into the plurality of apertures using a methodselected from the group consisting of wet processing, dry processing,mechanical pressing, thermal deposition, coating and any combination ofthese.

Optionally, the first ionically conductive and electronically insulatingmaterial is provided into the plurality of apertures by pressing thefirst high mechanical strength layer into the first ionically conductiveand electronically insulating material, thereby providing the firstionically conductive and electronically insulating material in at leasta portion of the plurality of apertures of the first high mechanicalstrength layer. Optionally, pressing the first high mechanical strengthlayer into the first ionically conductive and electronically insulatingmaterial occurs during formation of the first ionically conductive andelectronically insulating material. Optionally, pressing the first highmechanical strength layer into the first ionically conductive andelectronically insulating material occurs at a temperature of 400° C. orgreater or 500° C. or greater.

Optionally, the first high mechanical strength layer comprises a mesh ora foam. Optionally, the mesh or the foam comprises a metal, Ni,stainless steel, tin, Al, Cu, an alloy, a glass, a polymer, Kapton, PE,PP, PET, PTFE, PVDF, SiO₂, a ceramic, aluminum oxide, carbon, graphite,nanocarbon or any combination of these.

Optionally, the first ionically conductive and electronically insulatingmaterial is provided in substantially all of the plurality of aperturesof the first high mechanical strength layer. Optionally, the firstionically conductive and electronically insulating material fills all ofthe plurality of apertures of the first high mechanical strength layer.

Optionally, the first high mechanical strength layer comprises anelectronically insulating material. Optionally, the first highmechanical strength layer comprises Kapton, polyethylene, polypropylene,polyethylene terephthalate, poly(methyl methacrylate), a metal coatedwith a nonconductive material, an alloy coated with a nonconductivematerial, a polymer, a glass, an aluminum oxide, a silicon oxide, atitanium oxide and any combination of these. Optionally, the first highmechanical strength layer comprises one or more materials selected fromthe group consisting of Polyacrylic acid (PAA), Cross-linkedpolyethylene (PEX, XLPE), Polyethylene (PE), Polyethylene terephthalate(PET, PETE), Polyphenyl ether (PPE), Polyvinyl chloride (PVC),Polyvinylidene chloride (PVDC), Polylactic acid (PLA), Polypropylene(PP), Polybutylene (PB), Polybutylene terephthalate (PBT), Polyamide(PA), Polyimide (PI), Polycarbonate (PC), Polytetrafluoroethylene(PTFE), Polystyrene (PS), Polyurethane (PU), Polyester (PE),Acrylonitrile butadiene styrene (ABS), Poly(methyl methacrylate) (PMMA),Polyoxymethylene (POM), Polysulfone (PES), Styrene-acrylonitrile (SAN),Ethylene vinyl acetate (EVA), Styrene maleic anhydride (SMA), PVDF, PEO,LIPON, LISICON, tetramethylammonium hydroxide pentahydrate,(CH₃)₄NOH.5H₂O, poly(ethylene oxide) (PEO), copolymer of epichlorohydrinand ethylene oxide P(ECH-co-EO) and poly(vinylalcohol),PEO-PVA-glassfibre polymer electrolyte, zinc sulfide, silicon dioxide,PVA and PSA, PVA/V6/PSS; PVAN6/(PSS+PAA); V6/PVA/(PSS+PAA); PVMPSS+PAA(35%))/(PSS+PAA (35%)); (PSS+PAA (35%))/PVA/(PSS+PAA (35%)); or (PSS+PAA(35%))/(PVA (10%)+PSS (20% vs. PVA))/(PSS+PAA (35%)) polyethyleneglycol, polypropylene glycol, PEDOT:PSS, SiO₂, Lithium nitride, NaPON,PVC, glass fiber mat, polybutylene glycol, alkyl-polyethylene glycol,alkyl-polypropylene glycol, alkyl-polybutylene glycol, a copolymerthereof, a PEO material, a PVA material and any combination thereof.

Optionally, the first pattern of apertures provides a first porosity ofthe first high mechanical strength layer greater than or equal to 30%,greater than or equal to 50%, greater than or equal to 70%, selectedfrom the range of 30% to 90%, selected from the range of 30% to 70% orselected from the range of 40% to 60%. Optionally, the first highmechanical strength layer has an average thickness selected from therange 0.01 μm to 2000 μm. Optionally, the first high mechanical strengthlayer has an average thickness selected from the range 0.005 mm to 0.05mm.

Optionally, an electrochemical cell of this aspect further comprises afirst electronically and ionically conductive layer positioned betweenthe positive electrode and the separator and in electrical contact withthe positive electrode or positioned between the negative electrode andthe separator and in electrical contact with the negative electrode.Optionally, an electrochemical cell of this aspect further comprises asecond electronically and ionically conductive layer positioned betweenthe negative electrode and the separator and in electrical contact withthe negative electrode or positioned between the positive electrode andthe separator and in electrical contact with the positive electrode.

Optionally, the first electronically and ionically conductive layer is acomponent of the separator. Optionally, the first electronically andionically conductive layer is provided in physical contact and/orelectronic contact with the separator. Optionally, the firstelectronically and ionically conductive layer comprises a coating on theseparator. Optionally, the first electronically and ionically conductivelayer is in physical contact and/or electronic contact with the positiveelectrode or the negative electrode. Optionally, an electronically andionically conductive layer comprises an external current collector pole.Optionally, the first electronically and ionically conductive layercomprises a coating on the positive electrode or the negative electrode.Optionally, an electronically and ionically conductive layer reduces oneof the positive electrode and the negative electrode. Optionally, anexternal current collector pole oxidizes one of the positive electrodeand the negative electrode.

Optionally, the positive electrode or negative electrode comprises anintercalation host material. Optionally, the positive electrode ornegative electrode comprises a material that undergoes a change in shapeduring charging or discharging of the electrochemical cell. Optionally,the positive electrode comprises an active positive electrode materialand a current collector in electrical contact with the active positiveelectrode material. Optionally, the negative electrode comprises anactive negative electrode material and a current collector in electricalcontact with the active negative electrode material.

Optionally, in an electrochemical cell of this aspect, the separatorfurther comprises a second high mechanical strength layer having aplurality of apertures extending entirely through the second highmechanical strength layer and provided in a second pattern, the secondpattern having an off-set alignment relative to the first pattern suchthat an overlap of the apertures of the first high mechanical strengthlayer and the apertures of the second high mechanical strength layeralong axes extending perpendicularly from the first high mechanicalstrength layer through the second high mechanical strength layer is lessthan or equal to 20%; and wherein the first high mechanical strengthlayer and the second high mechanical strength layer are positioned suchthat ions of an electrolyte provided in contact with the first highmechanical strength layer and the second high mechanical strength layerare able to be transported through the first high mechanical strengthlayer and the second high mechanical strength layer. Optionally, in anelectrochemical cell of this aspect, the separator further comprises asecond ionically conductive and electronically insulating materialprovided in at least a portion of the plurality of apertures of thesecond high mechanical strength layer. Optionally, the first pattern issubstantially complementary to the second pattern. Optionally, the firsthigh mechanical strength layer and the second high mechanical strengthlayer are not in complete physical contact. Optionally, at leastportions of the first high mechanical strength layer and the second highmechanical strength layer are separated by a distance selected from therange of 20 nm to 2 mm. Optionally, the second high mechanical strengthlayer is provided between the first high mechanical strength layer andthe negative electrode or the positive electrode.

Optionally, in an electrochemical cell of this aspect, the separatorfurther comprises a third high mechanical strength layer having aplurality of apertures extending entirely through the third highmechanical strength layer and provided in a third pattern, the thirdpattern having an off-set alignment relative to the first pattern or thesecond pattern such that an overlap of the apertures of the third highmechanical strength layer and the apertures of the first high mechanicalstrength layer or the apertures of the second high mechanical strengthlayer along axes extending perpendicularly from the third highmechanical strength layer through first high mechanical strength layeror the second high mechanical strength layer is less than or equal to20%; and wherein the first high mechanical strength layer, the secondhigh mechanical strength layer and the third high mechanical strengthlayer are positioned such that ions of an electrolyte provided incontact with the first high mechanical strength layer, the second highmechanical strength layer and the third high mechanical strength layerare able to be transported through the first high mechanical strengthlayer, the second high mechanical strength layer and the third highmechanical strength layer. Optionally, in an electrochemical cell ofthis aspect, the separator further comprises a third ionicallyconductive and electronically insulating material provided in at least aportion of the plurality of apertures of the third high mechanicalstrength layer. Optionally, the third pattern is substantiallycomplementary to one or more of the first pattern and the secondpattern.

Optionally, in an electrochemical cell of this aspect, the separatorfurther comprises a fourth high mechanical strength layer having aplurality of apertures extending entirely through the fourth highmechanical strength layer and provided in a fourth pattern, the fourthpattern having an off-set alignment relative to the first pattern, thesecond pattern or the third pattern such that an overlap of theapertures of the fourth high mechanical strength layer and the aperturesof the first high mechanical strength layer, the apertures of the secondhigh mechanical strength layer or the apertures of the third highmechanical strength layer along axes extending perpendicularly fromfourth third high mechanical strength layer through first highmechanical strength layer, the second high mechanical strength layer orthe third high mechanical strength layer is less than or equal to 20%;and wherein the first high mechanical strength layer, the second highmechanical strength layer, the third high mechanical strength layer andthe fourth high mechanical strength layer are positioned such that ionsof an electrolyte provided in contact with the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer and the fourth high mechanical strengthlayer are able to be transported through the first high mechanicalstrength layer, the second high mechanical strength layer, the thirdhigh mechanical strength layer and the fourth high mechanical strengthlayer. Optionally, the separator further comprises a fourth ionicallyconductive and electronically insulating material provided in at least aportion of the plurality of apertures of the third high mechanicalstrength layer. Optionally, the fourth pattern is substantiallycomplementary to one or more of the first pattern, the second patternand the third pattern.

Optionally, the plurality of apertures of at least two high mechanicalstrength layers are filled with one or more solid electrolytes.Optionally, the plurality of apertures of two outer of the highmechanical strength layers are filled with one or more solidelectrolytes, such as an outer high mechanical strength layer positionedadjacent to the positive electrode or an outer high mechanical strengthlayer positioned adjacent to the negative electrode or both of these.Optionally, at least one high mechanical strength layer iselectronically conductive. Optionally, at least one high mechanicalstrength layer comprises a material having a thermal conductivitygreater than or equal to 5 W·m⁻¹·K⁻¹, greater than or equal to 10W·m⁻¹·K⁻¹, greater than or equal to 20 W·m⁻¹·K⁻¹, greater than or equalto 50 W·m⁻¹·K⁻¹, greater than or equal to 100 W·m⁻¹·K⁻¹ or greater thanor equal to 200 W·m⁻¹·K⁻¹. Optionally, at least one high mechanicalstrength layer, such as an outer high mechanical strength layerpositioned adjacent to the positive electrode or an outer highmechanical strength layer positioned adjacent to the negative electrodeor both, comprises an external current collector pole, useful forreducing one of the positive electrode and the negative electrode oroxidizing one of the positive electrode and the negative electrode.

In various embodiments, the electrochemical cell comprises a secondarybattery, a primary battery, a flow battery, an electrochemicalcapacitor, a semi-solid battery or a fuel cell. Optionally, theelectrochemical cell comprises a lithium ion battery, a lithium metalbattery, a zinc battery, a lithium-air battery, a zinc-air battery, analuminum air battery, an iron-air battery, a lithium-water battery, asilicon based battery, an alkaline battery or a lead acid battery.Optionally, the electrochemical cell comprises a secondary lithiumbattery comprising one or more of a silicon anode, a lithium anode, ametal oxide electrode, a carbon-based oxygen cathode, a carbon basedwater cathode, a water cathode and an air cathode.

In another aspect, provided are methods of making a membrane for anelectrochemical cell. In an embodiment of this aspect, the methodcomprises the steps of: providing a first high mechanical strength layerhaving a plurality of apertures extending entirely through the firsthigh mechanical strength layer and provided in a first pattern; andproviding a first ionically conductive and electronically insulatingmaterial into all or a portion of the plurality of apertures of thefirst high mechanical strength layer.

Optionally, the first ionically conductive and electronically insulatingmaterial is provided into the plurality of apertures using a methodselected from the group consisting of wet processing, dry processing,mechanical pressing, thermal deposition and any combination of these.Optionally, the first ionically conductive and electronically insulatingmaterial is provided into the plurality of apertures by pressing thefirst high mechanical strength layer into the first ionically conductiveand electronically insulating material, thereby providing the firstionically conductive and electronically insulating material in at leasta portion of the plurality of apertures of the first high mechanicalstrength layer. Optionally, a method of this aspect further comprises astep of cooling the first high mechanical strength layer and the firstionically conductive and electronically insulating material afterpressing. In embodiments, such a cooling step heals one or morefractures in the first ionically conductive and electronicallyinsulating material that are formed during a pressing step. Optionally,pressing the first high mechanical strength layer into the firstionically conductive and electronically insulating material occursduring formation of the first ionically conductive and electronicallyinsulating material. Optionally, wherein pressing the first highmechanical strength layer into the first ionically conductive andelectronically insulating material occurs at a temperature of 500° C. orgreater.

Optionally, the first high mechanical strength layer comprises a mesh ora foam. Optionally, the mesh or the foam comprises a metal, Ni,stainless steel, a glass, a ceramic, aluminum oxide. Optionally, anin-plane pressure on the first ionically conductive and electronicallyinsulating material from the first high mechanical strength layerfacilitates solid diffusions of ions through the first ionicallyconductive and electronically insulating material or helps with theuniform ion deposition on the electrode. Optionally, an in-planepressure on the first ionically conductive and electronically insulatingmaterial from the first high mechanical strength layer results in anincreased ionic conductivity of the first ionically conductive andelectronically insulating material when compared to an ionicconductivity of the first ionically conductive and electronicallyinsulating material in the absence of the in-plane pressure. Such anincrease in ionic conductivity optionally results from the Poisson'sratio effect where in-plane pressure causes out-of-plane tension,thereby facilitating the passage or solid diffusion of ions through theionically conductive and electronically insulating material.

Optionally, the first ionically conductive and electronically insulatingmaterial comprises a solid electrolyte, a gel electrolyte, a polymerelectrolyte, LISICON, NASICON, PEO, Li₁₀GeP₂S₁₂, LIPON, PVDF, Li₃N,Li₃P, LiI, LiBr, LiCl, LiF, oxide perovskite, La_(0.5), Li_(0.5)TiO₃,thio-LISICON, Li_(3.25)Ge_(0.25)P_(0.75)S₄, glass ceramics, Li₇P₃S₁₁,glassy materials, Li₂S—SiS₂—Li₃PO₄, lithium nitride, polyethylene oxide,Doped Li₃N, Li₂S—SiS₂—Li₃PO₄, LIPON, Li₁₄Zn(GeO₄)₄, Li-beta-alumina,Li_(3.6)Si_(0.6)P_(0.4)O₄, Li₂S—P₂S₅, PEO-LiClO₄,LiN(CF₃SO₂)₂/(CH₂CH₂O)₈, NaPON, ZrO₂, Nafion, PEDOT:PSS, SiO₂, PVC,glass fiber mat, alumina, silica glass, ceramics, glass-ceramics,water-stable polymers, glassy metal ion conductors, amorphous metal ionconductors, ceramic active metal ion conductors, glass-ceramic activemetal ion conductors, an ion conducting ceramic, an ion conducting solidsolution, an ion conducting glass, a solid lithium ion conductor or anycombination of these

Optionally, the first ionically conductive and electronically insulatingmaterial comprises 20% or more, 30% or more, 40% or more, 50% or more,60% or more, 70% or more or 80% or more by volume of the separator.Optionally, the first ionically conductive and electronically insulatingmaterial has an average thickness selected from the range 0.01 μm to2000 μm.

Optionally, the first ionically conductive and electronically insulatingmaterial has an average porosity less than 1%. Preferably, the firstionically conductive and electronically insulating material isnon-porous. Optionally, the first ionically conductive andelectronically insulating material has an average porosity selected fromthe range of 0% to 5%. Optionally, the first ionically conductive andelectronically insulating material is substantially free of pinholes,cracks, holes or any combination of these. Optionally, the firstionically conductive and electronically insulating material issubstantially free of defects. Optionally, the first ionicallyconductive and electronically insulating material is doped.

Optionally, the first ionically conductive and electronically insulatingmaterial has an ionic conductivity greater than or equal to 10⁻⁵ S/cm.Optionally, the first ionically conductive and electronically insulatingmaterial has an ionic conductivity selected from the range of 10⁻⁷S/cmto 100 S/cm.

Optionally, the first ionically conductive and electronically insulatingmaterial is provided in substantially all of the plurality of aperturesof the first high mechanical strength layer. Optionally, the firstionically conductive and electronically insulating material fills all ofthe plurality of apertures of the first high mechanical strength layer.

Optionally, an average thickness of the high mechanical strength layeris selected from the range of 10 nm to 2000 μm. Optionally, an averagethickness of the high mechanical strength layer is selected from therange of 0.005 mm to 0.05 mm. Optionally, the first pattern of aperturesprovides a first porosity of the first high mechanical strength layergreater than or equal to 30%. Optionally, the first pattern of aperturesprovides a porosity of the first high mechanical strength layer selectedfrom the range of 30% to 70%.

Optionally, the first high mechanical strength layer comprises anelectrically insulating material, Kapton, polyethylene, polypropylene,polyethylene terephthalate, poly(methyl methacrylate), a metal coatedwith a nonconductive material, an alloy coated with a nonconductivematerial, a polymer, a glass, a ceramic, an aluminum oxide, a siliconoxide, a titanium oxide and any combination of these. Optionally, thefirst high mechanical strength layer comprises one or more materialsselected from the group consisting of Polyacrylic acid (PAA),Cross-linked polyethylene (PEX, XLPE), Polyethylene (PE), Polyethyleneterephthalate (PET, PETE), Polyphenyl ether (PPE), Polyvinyl chloride(PVC), Polyvinylidene chloride (PVDC), Polylactic acid (PLA),Polypropylene (PP), Polybutylene (PB), Polybutylene terephthalate (PBT),Polyamide (PA), Polyimide (PI), Polycarbonate (PC),Polytetrafluoroethylene (PTFE), Polystyrene (PS), Polyurethane (PU),Polyester (PE), Acrylonitrile butadiene styrene (ABS), Poly(methylmethacrylate) (PMMA), Polyoxymethylene (POM), Polysulfone (PES),Styrene-acrylonitrile (SAN), Ethylene vinyl acetate (EVA), Styrenemaleic anhydride (SMA), PVDF, PEO, LIPON, LISICON, tetramethylammoniumhydroxide pentahydrate, (CH₃)₄NOH.5H₂O, poly(ethylene oxide) (PEO),copolymer of epichlorohydrin and ethylene oxide P(ECH-co-EO) andpoly(vinylalcohol), PEO-PVA-glassfibre polymer electrolyte, zincsulfide, silicon dioxide, PVA and PSA, PVA/V6/PSS; PVAN6/(PSS+PAA);V6/PVA/(PSS+PAA); PVMPSS+PAA (35%))/(PSS+PAA (35%)); (PSS+PAA(35%))/PVA/(PSS+PAA (35%)); or (PSS+PAA (35%))/(PVA (10%)+PSS (20% vs.PVA))/(PSS+PAA (35%)) polyethylene glycol, polypropylene glycol,polybutylene glycol, NaPON, ZrO₂, Nafion, PEDOT:PSS, SiO₂, PVC, glassfiber mat, alkyl-polyethylene glycol, alkyl-polypropylene glycol,alkyl-polybutylene glycol, a copolymer thereof, a PEO material, a PVAmaterial, Ni, Cu, Al, stainless steel, aluminum oxide and anycombination thereof.

Optionally, the first high mechanical strength layer comprises anelectrically conducting material, a metal, a metal alloy, a metal mesh,a semiconductor, a metal foam, polyethylene, polypropylene, polyethyleneterephthalate, poly(methyl methacrylate) and any combination of these.

In embodiments, the first high mechanical strength layer comprises anelectrically insulating material and the membrane comprises a separatorof an electrochemical cell. In embodiments, the first high mechanicalstrength layer comprises an electronically conductive material and themembrane comprises an electronically and ionically conductive layer ofan electrochemical cell. Optionally, the membrane comprises one or moreelectronically and ionically conductive layers and one or moreelectronically insulating and ionically conductive layers. Optionally,when such a membrane is positioned between a positive electrode and anegative electrode of an electrochemical cell, the membrane provideselectronic insulation between the positive electrode and the negativeelectrode.

Optionally, a method of this aspect further comprises a step ofproviding an electronically insulating layer adjacent to the first highmechanical strength layer with the first ionically conductive andelectronically insulating material in all or a portion of the pluralityof apertures of the first high mechanical strength layer.

Optionally, a method of this aspect further comprises a step ofproviding one or more current collectors adjacent to the first highmechanical strength layer with the first ionically conductive andelectronically insulating material in all or a portion of the pluralityof apertures of the first high mechanical strength layer. Optionally, afirst current collector is provided in electronic communication with anactive positive electrode material of an electrochemical cell and asecond current collector is provided in electronic communication with anactive negative electrode material of the electrochemical cell.

In another aspect, provided are electrochemical cells comprising: apositive electrode; a negative electrode; an ionically conductive andelectronically insulating separator positioned between the positiveelectrode and the negative electrode; one or more thermally andionically conductive layers positioned between the positive electrodeand the separator or positioned between the negative electrode and theseparator; and one or more electrolytes positioned between the positiveelectrode and the negative electrode; wherein the one or moreelectrolytes are capable of conducting charge carriers.

Optionally, the electrochemical cell comprises a first thermally andionically conductive layer positioned between the positive electrode andthe separator and a second thermally and ionically conductive layerpositioned between the negative electrode and the separator.

Optionally, each of the one or more thermally and ionically conductivelayers is provided in thermal communication with the positive electrodeor the negative electrode. Optionally, the one or more thermally andionically conductive layers provides for a uniform temperaturedistribution within the electrochemical cell, thereby increasing aperformance and a life cycle of the electrochemical cell. Optionally,the one or more thermally and ionically conductive layers assist toprovide for a uniform temperature distribution within theelectrochemical cell, thereby increasing a performance and a life cycleof the electrochemical cell.

Optionally, each of the one or more thermally and ionically conductivelayers independently has a thickness less than or equal to 0.01 mm orselected from the range of 10 nm to 0.01 mm. Optionally, each of the oneor more thermally and ionically conductive layers independentlycomprises a porous material, a perforated layer, a mesh or a foam.Optionally, each of the one or more thermally and ionically conductivelayers independently has a porosity greater than or equal to 50%,greater than or equal to 75% or greater than or equal to 90%.

Optionally, each of the one or more thermally and ionically conductivelayers independently comprises a metal, an alloy, a ceramic, a polymer,a metal coated with an electronically insulating material or an alloycoated with an electronically insulating material. Optionally, each ofthe one or more thermally and ionically conductive layers independentlycomprises a metal, an alloy, a thermal conductive polymer, a thermalconductive ceramic, a polymer having thermally conductive fibers, apolymer having Al₂O₃ fibers, Al, Ni, Sn, Steel, stainless steel, copper,Si, Li₃N, aluminum oxide, lithium oxide, lithium peroxide, polyethylene,polypropylene, polyethylene terephthalate, PVDF, Kapton, PTFE, PMMA,NaPON, ZrO₂, Nafion, PEDOT:PSS, SiO₂, PVC, glass fiber mat, LIPON or anycombination thereof.

Optionally, each of the one or more thermally and ionically conductivelayers independently comprises a mesh. Optionally, each of the one ormore thermally and ionically conductive layers independently comprises acoating on one or more surfaces of the positive electrode or thenegative electrode.

Optionally, each of the one or more thermally and ionically conductivelayers independently comprises a coating on one or more sides of theseparator or is positioned adjacent to the separator. Optionally, eachof the one or more thermally and ionically conductive layersindependently comprises an interior layer of the separator.

Optionally, for any electrochemical cell described herein, any faces ofa separator, a negative electrode or a positive electrode areindependently and optionally coated with a hydrophilic material or ahydrophobic material or an anion exchange material or a cation exchangematerial. Optionally, any layers of a separator, a positive electrode ora negative electrode independently comprise a hydrophilic material or ahydrophobic material or an anion exchange material or a cation exchangematerial.

Optionally, any layers of a separator, a positive electrode or anegative electrode independently comprise a shape memory material.Optionally, a shape memory material comprises a shape memory alloy,nitinol, a shape memory polymers or any combination thereof. Optionally,a shape memory material layer is pre stressed before operation orcycling of the electrochemical cell.

In another aspect, provided are electrochemical cells comprising: apositive electrode; a negative electrode; a solid electrolytecomprising: a first ionically conductive and electronically insulatingmaterial; and a group of mechanically tough fibers positioned inside afirst ionically conductive and electronically insulating material;wherein the electrolyte is capable of conducting charge carriers.Optionally, the fibers increase a toughness of the solid electrolyte,prevent pinhole cracks during fabrication of the solid electrolyte andprevent cracks in the solid electrolyte due to cycling.

Optionally, the fibers are mechanically tough. Optionally, the fiberscomprise 20% or more by volume of the first ionically conductive andelectronically insulating material or occupy 20% or more of a surfacearea of the separator. Optionally, the fibers have an average sizeselected from the range 0.01 μm to 2000 μm. Optionally, the firstionically conductive and electronically insulating material has anaverage thickness selected from the range 0.01 μm to 2000 μm.Optionally, fibers are ionically insulating. Optionally, fibers areionically conductive. Optionally, the fibers are electronicallyconductive. Optionally, the fibers are electronically insulating.

For any of the electrochemical cells described herein, a high mechanicalstrength layer optionally comprises a shape memory material selectedfrom the group consisting of shape memory alloys, shape memory polymers,nitonol and any combination of these. For any of the electrochemicalcells described herein, a high mechanical strength layer is optionallyelectronically conductive. For any of the electrochemical cellsdescribed herein, a high mechanical strength layer is optionallyelectronically insulating. For any of the electrochemical cellsdescribed herein, a high mechanical strength layer is optionallymechanically tough. For any of the electrochemical cells describedherein, a high mechanical strength layer optionally comprises a shapememory material or optionally comprises a shape memory alloy, a shapememory polymer, nitonol or any combination of these. For any of theelectrochemical cells described herein, a high mechanical strength layeroptionally has a periodic geometry or comprises a mesh. For any of theelectrochemical cells described herein, a high mechanical strength layeroptionally has a non-periodic geometry or an arbitrary cross section.For any of the electrochemical cells described herein, a high mechanicalstrength layer is optionally used to prevent creation of pinholes duringthe fabrication of the first ionically conductive and electronicallyinsulating material. For any of the electrochemical cells describedherein, a high mechanical strength layer is optionally used to preventcreation of pinholes during the fabrication of the first ionicallyconductive and electronically insulating material. For any of theelectrochemical cells described herein, a high mechanical strength layeris optionally used to prevent creation of cracks due to diffusion ofions in the first ionically conductive and electronically insulatingmaterial. For any of the electrochemical cells described herein, a highmechanical strength layer is optionally partially bounded to anelectrode and the first ionically conductive and electronicallyinsulating material. Optionally, a first high mechanical strength layerpositions an ionically conductive and electronically insulating materialand an electrode in tight contact. Optionally, a high mechanicalstrength layer has a shape memory behavior or comprises a shape memoryalloy, a shape memory polymer or nitonol. Optionally, first highmechanical strength layer is prestressed. For any of the electrochemicalcells described herein, a high mechanical strength layer optionally hasa 3-dimensional structure or comprises a 3-dimensional mesh. Optionally,high mechanical strength layer is prestressed. Optionally, a highmechanical strength layer is prestressed, thereby providing physicalcontact between one or more ionically conductive and electronicallyinsulating materials and an electrode. Optionally, the fibers or themesh of an electrochemical cell has a binding effect and binds aionically conductive and electronically insulating material together.For any of the electrochemical cells described herein, a fiber or meshoptionally comprises a polymer or PVDF polymer or rubber.

Optionally, any separators and/or membranes described herein, forexample single or multilayer separators comprising a high mechanicalstrength layer including a plurality of apertures, are useful for avariety of applications. In an embodiment, any separators and/ormembranes described herein are used as separator of an electrochemicalcell. In an embodiment, any separators and/or membranes described hereinare used as a liquid filtration membrane. In an embodiment, anyseparators and/or membranes described herein are used as a gaseousfiltration membrane. In an embodiment, any separators and/or membranesdescribed herein are used as engineered electrodes in electrochemicalcells. In an embodiment, any separators and/or membranes describedherein are used as a filter used for industrial filtration. In anembodiment, any separators and/or membranes described herein are used asa bio-filtration membrane. In an embodiment, any separators and/ormembranes described herein are used in as an industrial filtrationmembrane in the food industry. In an embodiment, any separators and/ormembranes described herein are used in as an industrial filtrationmembrane in the pharmaceutical industry.

The disclosed separators and membranes are suitable for use and/or areoptionally used in condensation and separation of substances by reverseosmosis, ultrafiltration, fine filtration, production of a highlypurified water or chemicals of high degrees of purity used insemiconductor industries; collection of effluents from defatting processor electrodeposition process; treatment of waste liquids in variousindustrial processes such as paper-making process, oil-water separationprocess, oily emulsion separation process, etc.; separation and refiningof fermented products; condensation, separation and refining in variousfood industries such as condensation of fruit and vegetable juices,processing of soybean, production of sugar, etc.; medical uses includingartificial kidney, micro-filter for separation of blood components andbacterium, and separator or refiner for medical drugs; bio-technologicaldevices including bio-reactors; and electrodes of a fuel battery.

In an embodiment, the invention provides any electrochemical cell asdescribed herein, wherein the electrochemical cell comprises anelectronically conductive layer that is not in electronic and/orphysical contact with a cathode of the cell, for example, anelectrochemical cell wherein the electronically conductive layer is inelectronic and/or physical contact with an anode of the cell.

In an embodiment, the invention provides an electrochemical cell asdescribed herein, wherein the electrochemical cell comprises anelectronically conductive layer that is not in electronic and/orphysical contact with an anode of the cell, for example, anelectrochemical cell wherein the electronically conductive layer is inelectronic and/or physical contact with a cathode of the cell.

In an embodiment, the invention provides an electrochemical cell asdescribed herein, wherein the electrochemical cell comprises anelectronically conductive layer in electronic and/or physical contactwith an electrode that is not a fluid electrode, for example, anelectrochemical cell wherein the electronically conductive layer is inelectronic and/or physical contact with an electrode that is not an airelectrode or an oxygen electrode.

Optionally, in any electrochemical cell described herein, theelectrochemical cell does not include any electronically conductivelayer, such as an electronically conductive layer of a separator, inelectronic and/or physical contact with a cathode. Optionally, in anyelectrochemical cell described herein, the electrochemical cell does notinclude any electronically conductive layer, such as an electronicallyconductive layer of a separator, in electronic and/or physical contactwith a positive electrode.

Optionally, in any electrochemical cell described herein, theelectrochemical cell does not include any electronically conductivelayer, such as an electronically conductive layer of a separator, inelectronic and/or physical contact with an anode. Optionally, in anyelectrochemical cell described herein, the electrochemical cell does notinclude any electronically conductive layer, such as an electronicallyconductive layer of a separator, in electronic and/or physical contactwith a negative electrode. Optionally, in any electrochemical celldescribed herein, a metal layer comprises a porous metal layer or aperforated metal layer.

Optionally, in any electrochemical cell described herein, theelectrochemical cell does not include any electronically conductivelayer, such as an electronically conductive layer of a separator, inelectronic and/or physical contact with a fluid electrode. Optionally,in any electrochemical cell described herein, the electrochemical celldoes not include any electronically conductive layer, such as anelectronically conductive layer of a separator, in electronic and/orphysical contact with an air or oxygen electrode.

Without wishing to be bound by any particular theory, there can bediscussion herein of beliefs or understandings of underlying principlesor mechanisms relating to the invention. It is recognized thatregardless of the ultimate correctness of any explanation or hypothesis,an embodiment of the invention can nonetheless be operative and useful.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a side perspective view of a multilayer separator systemfor an electrochemical system comprising parallel first and second highmechanical strength layers having complementary patterns of apertures,wherein the second pattern of apertures has an off-set alignmentrelative to the first pattern such that there is no overlap of theapertures of the first pattern and the apertures of the second patternalong axes extending perpendicularly from the first high mechanicalstrength layer to the second high mechanical strength layer.

FIG. 2 provides a side perspective view of a multilayer separator systemfor an electrochemical system comprising parallel first and second highmechanical strength layers having complementary patterns of apertures,wherein the second pattern of apertures has an off-set alignmentrelative to the first pattern such that there is a selected extent ofoverlap of the apertures of the first pattern and the apertures of thesecond pattern along axes extending perpendicularly from the first highmechanical strength layer to the second high mechanical strength layer,for example, a selected extent of overlap minimizing or avoid dendritegrowth through the separator system.

FIG. 3 provides a schematic diagram illustrating a cross sectional viewof a multilayer separator system of the invention having first andsecond patterned high mechanical strength layers separated by anelectrolyte-containing layer.

FIG. 4 provides a schematic diagram illustrating a cross sectional viewof a multilayer separator system of the invention having first, secondand third patterned high mechanical strength layers separated byelectrolyte-containing layers.

FIG. 5 provides a schematic diagram illustrating a cross sectional viewof a multilayer separator system of the invention showing theorientation of apertures and solid regions of the first and secondpatterned high mechanical strength layers separated byelectrolyte-containing layers.

FIG. 6 provides a schematic diagram illustrating a cross sectional viewof a multilayer separator system of the invention showing theorientation of apertures and solid regions of the first, second andthird patterned high mechanical strength layers separated byelectrolyte-containing layers.

FIG. 7 provides a schematic diagram providing a cross sectional view ofa lithium battery of the invention comprising a separator system withtwo patterned high mechanical strength layers having complementarypatterns of apertures.

FIG. 8 provides a schematic diagram providing a cross sectional view ofa lithium battery of the invention comprising a separator system withfour patterned high mechanical strength layers having complementarypatterns of apertures.

FIG. 9 provides a schematic diagram providing a cross sectional view ofan electrochemical cell of the invention comprising a separator systemwith three patterned high mechanical strength layers havingcomplementary patterns of apertures.

FIG. 10A provides a schematic diagram providing a cross sectional viewof an electrochemical cell of the invention comprising a lithium metalanode, cathode and a separator system comprising three high mechanicalstrength layers having complementary patterns of apertures, two lowionic resistance layers, two electrolyte containing voids and a framecomponent.

FIG. 10B provides a schematic diagram providing a cross sectional viewof an electrochemical cell (e.g. useful for Li-air, Li-water batteries)having a separator with a protective solid electrolyte, wherein thesolid electrolyte conducts the desired ions (such as Li⁺) but isimpermeable to water, air, CO₂, contaminations and materials thatdeteriorate the performance of the electrochemical cell.

FIG. 10C provides a schematic diagram providing a cross sectional viewof an electrochemical cell (e.g., useful for Li-air, Li-water batteries)having a separator with a protective solid electrolyte, wherein thesolid electrolyte conducts the desired ions (such as Li⁺) but isimpermeable to water, air, CO2, contaminations and materials thatdeteriorate the performance of the electrochemical cell.

FIG. 10D provides a schematic diagram providing a cross sectional viewof an electrochemical cell (e.g., useful for Li-Sulfur batteries) havingseparator with a protective solid electrolyte, wherein the solidelectrolyte conducts the desired ions (such as Li⁺) but is impermeableto particle passage between cathode and anode that deteriorate theperformance of the electrochemical cell.

FIG. 10E provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the conductiveside of the separator next to the anode reduces anode loss; e.g., bystopping the dendrite growth, reducing anode loss such as in mossydeposition and stop the passage of cathode materials to the anode uponcycling which breaks the electronic contact between anode particles andthe current collector and deteriorate the performance of theelectrochemical cell.

FIG. 10F provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the perforatedseparator plates and the porous layers act as a separator by providingelectronic insulation between the electrodes, yet providing ionicconnection between the electrodes via a fluid electrolyte (aqueous oraprotic).

FIG. 10G provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein shape memoryeffect of the two high mechanical strength layers results in a very goodmechanical contact between the separator and the electrodes.

FIG. 10H provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the superelasticity and/or shape memory effect of the two high mechanicalstrength layers results in a very good mechanical contact between theseparator and the electrodes.

FIG. 10I provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the superelasticity and/or shape memory effect of two high mechanical strengthlayers results in a very good mechanical contact between the separatorand the electrodes.

FIG. 10J provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the conductiveside of the separator reduces anode loss such as in silicon largedeformations upon cycling which breaks the electronic contact betweenanode particles and the current collector and deteriorate theperformance of the electrochemical cell.

FIG. 10K provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the conductiveside of the separator next to the anode reduces anode loss such as insilicon large deformations upon cycling which breaks the electroniccontact between anode particles and the current collector anddeteriorate the performance of the electrochemical cell.

FIG. 10L provides a schematic diagram providing a cross sectional viewof an electrochemical cell.

FIG. 10M provides a schematic diagram providing a cross sectional viewof an electrochemical cell.

FIG. 10N provides a schematic diagram providing a cross sectional viewof an electrochemical cell.

FIG. 10O provides a schematic diagram providing a cross sectional viewof an electrochemical cell.

FIG. 10P provides a schematic diagram providing a cross sectional viewof an electrochemical cell.

FIGS. 11A and 11B provide examples of the designs of porous, patternedlayers of some separator systems of the invention.

FIG. 12 provides a schematic diagram of a cross sectional view of anelectrochemical cell including a separator system of the invention.

FIG. 13 provides a schematic diagram illustrating a required trajectoryof dendrite growth in order to make a short in an electrochemical systemof the invention.

FIG. 14 (Panels A-M) provides examples of complementary patterns ofapertures useful in the patterned high mechanical strength layers ofseparator systems of the invention.

FIG. 15 provides a plot of charge and discharge capacities (mAh/g) as afunction of number of cycles for an electrochemical cell having: (A) amultilayer separator system of the invention having an overall thicknessof 125 microns and (B) a Celgard separator having a thickness of 25microns.

FIG. 16 provides a plot of charge and discharge capacities (mAh/g) as afunction of number of cycles for: (A, lines 1, 5 and 6)) anelectrochemical cell having a multilayer separator system of theinvention, a Li metal anode and a LiCoO₂ cathode as compared to (B,lines 2 and 3) an electrochemical cell having a conventional separator.

FIG. 17 provides a plot of charge and discharge capacities (mAh/g) as afunction of number of cycles for: (lines A, B and C) an electrochemicalcell having a multilayer separator system of the invention, a Li metalanode and a LiCoO₂ cathode as compared to (lines F and D) show areference electrode made with a perforated Kapton between two Celgardlayers and (lines H and I) a Celgard separator having a thickness of 25microns.

FIG. 18 provides a schematic diagram illustrating an electrochemicalcell of the invention having a multilayer separator comprising threehigh mechanical strength layers with complementary patterns ofapertures.

FIG. 19 provides a schematic diagram illustrating the trajectory of Li⁺ions passing through the multilayer separator shown in FIG. 18.

FIG. 20 provides a plot of cell voltage (V vs Li) versus cycling time(h) for the galvanostatic lithium stripping from two symmetrical ( 5/9)″lithium chips separated by a multi-layer separator of the invention.

FIG. 21 provides plots of the current [milliAmpere] vs. time [hr] andvoltage [v] vs. time [hr].

FIG. 22 provides a plot of current [A] (on top) and voltage [v] (onbottom) as a function of time [s] in a CR2032 cell made with Li-metal,LiFePO₄ cathode separated by a multi-layer separator of the invention.

FIGS. 23 and 24 provide photographs of perforated layers useful inseparator systems of some embodiments and experiments.

FIGS. 25, 26, 27, 28, 29 and 30 provide photographs of perforated layersuseful in separator systems of some embodiments.

FIG. 31 provides a cross sectional view of an electrochemical cellembodiment including a composite membrane.

FIG. 32 depicts various composite membrane embodiments.

FIGS. 33A-33D provide schematic cross-sectional views of anelectrochemical cell before (FIG. 33A) and after (FIG. 33B) charging,and after multiple charge/discharge cycles (FIG. 33C and FIG. 33D).

FIGS. 34-43 provide plots showing experimental data obtained fromelectrochemical cells in which an ionically and electronicallyconductive layer was positioned adjacent to an electrode.

FIGS. 44-49 provide schematic cross-sectional views of electrochemicalcell embodiments including one or more conductive layers.

DETAILED DESCRIPTION

In general the terms and phrases used herein have their art-recognizedmeaning, which can be found by reference to standard texts, journalreferences and contexts known to those skilled in the art. The followingdefinitions are provided to clarify their specific use in the context ofthe invention.

Referring to the drawings, like numerals indicate like elements and thesame number appearing in more than one drawing refers to the sameelement. In addition, hereinafter, the following definitions apply:

The term “electrochemical cell” refers to devices and/or devicecomponents that convert chemical energy into electrical energy orelectrical energy into chemical energy. Electrochemical cells have twoor more electrodes (e.g., positive and negative electrodes) and anelectrolyte, wherein electrode reactions occurring at the electrodesurfaces result in charge transfer processes. Electrochemical cellsinclude, but are not limited to, primary batteries, secondary batteriesand electrolysis systems. In certain embodiments, the termelectrochemical cell includes fuel cells, supercapacitors, capacitors,flow batteries, metal-air batteries and semi-solid batteries. Generalcell and/or battery construction is known in the art, see e.g., U.S.Pat. Nos. 6,489,055, 4,052,539, 6,306,540, Seel and Dahn J. Electrochem.Soc. 147(3) 892-898 (2000).

The term “capacity” is a characteristic of an electrochemical cell thatrefers to the total amount of electrical charge an electrochemical cell,such as a battery, is able to hold. Capacity is typically expressed inunits of ampere-hours. The term “specific capacity” refers to thecapacity output of an electrochemical cell, such as a battery, per unitweight. Specific capacity is typically expressed in units ofampere-hours kg⁻¹.

The term “discharge rate” refers to the current at which anelectrochemical cell is discharged. Discharge rate can be expressed inunits of ampere. Alternatively, discharge rate can be normalized to therated capacity of the electrochemical cell, and expressed as C/(X t),wherein C is the capacity of the electrochemical cell, X is a variableand t is a specified unit of time, as used herein, equal to 1 hour.

“Current density” refers to the current flowing per unit electrode area.

Electrode refers to an electrical conductor where ions and electrons areexchanged with electrolyte and an outer circuit. “Positive electrode”and “cathode” are used synonymously in the present description and referto the electrode having the higher electrode potential in anelectrochemical cell (i.e. higher than the negative electrode).“Negative electrode” and “anode” are used synonymously in the presentdescription and refer to the electrode having the lower electrodepotential in an electrochemical cell (i.e. lower than the positiveelectrode). Cathodic reduction refers to a gain of electron(s) of achemical species, and anodic oxidation refers to the loss of electron(s)of a chemical species. Positive electrodes and negative electrodes ofthe present electrochemical cell may further comprise a conductivediluent, such as acetylene black, carbon black, powdered graphite, coke,carbon fiber, graphene, and metallic powder, and/or may furthercomprises a binder, such as a polymer binder. Useful binders forpositive electrodes in some embodiments comprise a fluoropolymer such aspolyvinylidene fluoride (PVDF). Positive and negative electrodes of thepresent invention may be provided in a range of useful configurationsand form factors as known in the art of electrochemistry and batteryscience, including thin electrode designs, such as thin film electrodeconfigurations. Electrodes are manufactured as disclosed herein and asknown in the art, including as disclosed in, for example, U.S. Pat. Nos.4,052,539, 6,306,540, and 6,852,446. For some embodiments, the electrodeis typically fabricated by depositing a slurry of the electrodematerial, an electrically conductive inert material, the binder, and aliquid carrier on the electrode current collector, and then evaporatingthe carrier to leave a coherent mass in electrical contact with thecurrent collector.

“Electrode potential” refers to a voltage, usually measured against areference electrode, due to the presence within or in contact with theelectrode of chemical species at different oxidation (valence) states.

“Electrolyte” refers to an ionic conductor which can be in the solidstate, the liquid state (most common) or more rarely a gas (e.g.,plasma).

“Standard electrode potential”) (E°) refers to the electrode potentialwhen concentrations of solutes are 1M, the gas pressures are 1 atm andthe temperature is 25 degrees Celsius. As used herein standard electrodepotentials are measured relative to a standard hydrogen electrode.

“Active material” refers to the material in an electrode that takes partin electrochemical reactions which store and/or deliver energy in anelectrochemical cell.

“Cation” refers to a positively charged ion, and “anion” refers to anegatively charged ion.

“Electrical contact,” “electrical communication”, “electronic contact”and “electronic communication” refer to the arrangement of one or moreobjects such that an electric current efficiently flows from one objectto another. For example, in some embodiments, two objects having anelectrical resistance between them less than 100Ω are considered inelectrical communication with one another. An electrical contact canalso refer to a component of a device or object used for establishingelectrical communication with external devices or circuits, for examplean electrical interconnection. “Electrical communication” also refers tothe ability of two or more materials and/or structures that are capableof transferring charge between them, such as in the form of the transferof electrons. In some embodiments, components in electricalcommunication are in direct electrical communication wherein anelectronic signal or charge carrier is directly transferred from onecomponent to another. In some embodiments, components in electricalcommunication are in indirect electrical communication wherein anelectronic signal or charge carrier is indirectly transferred from onecomponent to another via one or more intermediate structures, such ascircuit elements, separating the components.

“Thermal contact” and “thermal communication” are used synonymously andrefer to an orientation or position of elements or materials, such as acurrent collector or heat transfer rod and a heat sink or a heat source,such that there is more efficient transfer of heat between the twoelements than if they were thermally isolated or thermally insulated.Elements or materials may be considered in thermal communication orcontact if heat is transported between them more quickly than if theywere thermally isolated or thermally insulated. Two elements in thermalcommunication or contact may reach thermal equilibrium or thermal steadystate and in some embodiments may be considered to be constantly atthermal equilibrium or thermal steady state with one another. In someembodiments, elements in thermal communication with one another areseparated from each other by a thermally conductive material orintermediate thermally conductive material or device component. In someembodiments, elements in thermal communication with one another areseparated by a distance of 1 μm or less. In some embodiments, elementsin thermal communication with one another are provided in physicalcontact.

“High mechanical strength” refers to a property of components ofseparator systems of the invention, such as first, second, third andfourth high mechanical strength layers, having a mechanical strengthsufficient to prevent physical contact of opposite electrodes,sufficient to prevent short circuiting due to external objects withinthe cell, such as metallic particles from fabrication, and sufficient toprevent short circuiting due to growth of dendrites between positive andnegative electrodes of an electrochemical cell, for example, duringcharge and discharge cycles of a secondary electrochemical cell. In anembodiment, for example, a high mechanical strength layer has amechanical strength sufficient to prevent piercing due to externalobjects in the cell, such as metallic particles from the fabrication,and shorts due to the growth of dendrites between electrodes. In anembodiment, for example, a high mechanical strength layer has amechanical strength sufficient to prevent shorting between the positiveelectrode and the negative electrode of an electrochemical cell due toexternal objects in the cell such as metallic particles from thefabrication and shorts due to the growth of dendrites betweenelectrodes. In an embodiment, for example, a high mechanical strengthlayer is characterized by a Young's modulus greater than or equal to 500MPa, and optionally for some applications a Young's modulus greater thanor equal to 1 GPa, and optionally for some applications a Young'smodulus greater than or equal to 10 GPa, and optionally for someapplications a Young's modulus greater than or equal to 100 GPa. In anembodiment, for example, a high mechanical strength layer ischaracterized by a yield strength greater than or equal to 5 MPa, andoptionally for some applications a yield strength greater than or equalto 50 MPa, and optionally for some applications a yield strength greaterthan or equal to 100 MPa, and optionally for some applications a yieldstrength greater than or equal to 500 MPa. In an embodiment, forexample, a high mechanical strength layer is characterized by apropagating tear strength greater than or equal to 0.005 N, andoptionally for some applications a propagating tear strength greaterthan or equal to 0.05 N, a propagating tear strength greater than orequal to 0.5 N, a propagating tear strength greater than or equal to 1N. In an embodiment, for example, a high mechanical strength layer ischaracterized by an initiating tear strength greater than or equal to 10N, and optionally for some applications an initiating tear strengthgreater than or equal to 100 N. In an embodiment, for example, a highmechanical strength layer is characterized by a tensile strength greaterthan or equal to 50 MPa, and optionally for some applications a tensilestrength greater than or equal to 100 MPa, and optionally for someapplications a tensile strength greater than or equal to 500 MPa, andoptionally for some applications a tensile strength greater than orequal to 1 GPa. In an embodiment, for example, a high mechanicalstrength layer is characterized by an impact strength greater than orequal to 10 N cm, and optionally for some applications to an impactstrength greater than or equal to 50 N cm, and optionally for someapplications to an impact strength greater than or equal to 100 N cm,and optionally for some applications to an impact strength greater thanor equal to 500 N cm.

“Chemically resistant” refers a property of components, such as layers,of separators and electrochemical systems of the invention wherein thereis no significant chemical or electrochemical reactions with the cellactive materials, such as electrodes and electrolytes. In certainembodiments, chemically resistant also refers to a property wherein thetensile retention and elongation retention is at least 90% in theworking environment of an electrochemical system, such as anelectrochemical cell.

“Thermally stable” refers a property of components, such as layers, ofseparators and electrochemical systems of the invention wherein there isno significant chemical or electrochemical reactions due to normal andoperational thermal behavior of the cell. In certain embodiments,thermally stable also refers to materials wherein the melting point ismore than 100 Celsius, and preferably for some embodiments more than 300Celsius, and optionally the coefficient of thermal expansion is lessthan 50 ppm/Celsius. In an embodiment, thermally stable refers to aproperty of a component of the separator system such that it may performin a rechargeable electrochemical cell without undergoing a change sizeor shape with the temperature that significantly degrades theperformance of the electrochemical cell.

“Porosity” refers to the amount of a material or component, such as ahigh mechanical strength layer, that corresponds to pores, such asapertures, channels, voids, etc. Porosity may be expressed as thepercentage of the volume of a material, structure or device component,such as a high mechanical strength layer, that corresponds to pores,such as apertures, channels, voids, etc., relative to the total volumeoccupied by the material, structure or device component.

Provided are separator systems for electrochemical systems providingelectronic, mechanical and chemical properties useful for a range ofelectrochemical storage and conversion applications. Some embodiments,for example, provide structural, physical and electrostatic attributesuseful for managing and controlling dendrite formation in lithium andzinc based batteries or flow batteries. Some of the disclosed separatorsystems include multilayer, porous geometries supporting excellent iontransport properties while at the same time providing a barriereffective to prevent dendrite initiated mechanical failure, shortingand/or thermal runaway. Some embodiments, for example, providestructural, physical and electrostatic attributes useful for improvingthe cycle life and rate capability of electrochemical cells such assilicon anode based batteries or air cathode based batteries or redoxfellow batteries or semisolid batteries. Disclosed separator systemsinclude multilayer, porous geometries supporting excellent ion transportproperties while at the same time providing an auxiliary path effectiveto increase the electronic conductivity of the electrodes or improvingthe uniformity of the electric field. Some embodiments, for example,provide structural, physical and electrostatic attributes useful forimproving the cycle life and rate capability of electrochemical cells insolid electrolyte based systems such as Li-air batteries or fuel cellsor flow batteries or semisolid batteries. Disclosed separator systemsinclude composite solid electrolyte/supporting mesh systems and solidelectrolyte/supporting fibers systems providing the hardness and safetyof solid electrolytes with the toughness and long life of the supportingmesh or fibers which is useful in fabrication and operation of thinsolid electrolyte without fabrication pinholes and without operationalcreated cracks that happen in conventional solid electrolytes.

Separators and membranes introduced here are suitable for use incondensation and separation of substances by, for example, reverseosmosis, ultrafiltration, fine filtration, production of a highlypurified water or chemicals of high degrees of purity used insemiconductor industries; collection of effluents from defatting processor electrodeposition process; treatment of waste liquids in variousindustrial processes such as paper-making process, oil-water separationprocess, oily emulsion separation process, and so forth; separation andrefining of fermented products; condensation, separation and refining invarious food industries such as condensation of fruit and vegetablejuices, processing of soybean, production of sugar, and so forth;medical uses such as artificial kidney, micro-filter for separation ofblood components and bacterium, and separator or refiner for medicaldrugs; bio-technological devices such as a bio-reactor; electrodes of afuel battery

FIG. 1 provides a side perspective view of a multilayer separator system100(1) for an electrochemical system comprising parallel first andsecond high mechanical strength layers having complementary patterns ofapertures, wherein the second pattern of apertures has an off-setalignment relative to the first pattern such that there is no overlap ofthe apertures of the first pattern and the apertures of the secondpattern along axes extending perpendicularly from the first highmechanical strength layer to the second high mechanical strength layer.As shown in FIG. 1, separator system 100(1) comprises a first highmechanical strength layer 102(1) having a first pattern comprising aplurality of apertures, e.g. 104(1) and 104(4), and a second highmechanical strength layer 102(2) having a second pattern comprising asecond plurality of apertures, e.g. 104(2) and 104(3). First and secondlayers are characterized by a planar geometry and lateral dimensions,such as height, H, length, L, and width or thickness, W. As shown inFIG. 1, apertures 104 extend entirely through the thickness of eitherfirst high mechanical strength layer 102(1) or second high mechanicalstrength layer 102(2). Each aperture 104 is also characterized bylateral dimensions, such as height, h, length, l, and width or thickness(not shown).

The superposition of the pattern of first high mechanical strength layer102(1) onto the second high mechanical strength layer 102(2) isschematically presented as a plurality of off-set dashed areas 106(1) onsecond high mechanical strength layer 102(2), and the superposition ofthe pattern of second high mechanical strength layer 102(2) on firsthigh mechanical strength layer 102(1) is schematically presented as aplurality of off-set dashed areas 106(2) on first high mechanicalstrength layer 102(1). In the embodiment shown in FIG. 1, the first andsecond patterns resemble checkerboard patterned, for example where thefirst pattern corresponds to the back squares and the second patterncorresponds to the red squares of a checker board. As will be apparentto one of skill in the art, however, other patterns, such as honeycombpatterns, close-packed circle patterns, brick patterns, triangularpatterns and the like, are also possible, so long as the first andsecond patterns have off-set alignments relative to one another, forexample, such that an overlap of apertures 104 along axes extendingperpendicularly from first high mechanical strength layer 102(1) tosecond high mechanical strength layer 102(2) is less than or equal to50%, 40%, 30%, 20%, 10%, 5%, 2% or 0%. In the embodiment shown in FIG.1, there is no overlap of the apertures of the first pattern and theapertures of the second pattern along axes extending perpendicularlyfrom the first high mechanical strength layer to the second highmechanical strength layer. The arrows 108(1) and 108(2) shown in FIG. 1are provided so as to illustrate regions of the apertures that do notoverlap along axes extending perpendicularly from first high mechanicalstrength layer 102(1) to second high mechanical strength layer 102(2).The off-set alignment of the first pattern of apertures of the firsthigh mechanical strength layer and the second pattern of apertures ofthe second high mechanical strength layer prevents growth of dendritesthrough the combination of first and second high mechanical strengthlayers, for example, by mechanically blocking growing dendrites and/orrequiring a pathway involving curved trajectories which arethermodynamically and/or kinetically unfavorable. For example, adendrite may only pass through aperture 104(3) of second high mechanicalstrength layer 102(2), as shown by arrow A, because it is physicallyblocked by first high mechanical strength layer 102(1) at point 110(1).Similarly, a dendrite may only pass through aperture 104(4) of firsthigh mechanical strength layer 102(1), as shown by arrow B, because itis physically blocked by second high mechanical strength layer 102(2) atpoint 110(2).

FIG. 2 provides a side perspective view of a multilayer separator system100(2) for an electrochemical system comprising parallel first andsecond high mechanical strength layers having complementary patterns ofapertures, wherein the second pattern of apertures has an off-setalignment relative to the first pattern such that there is a selectedextent of overlap of the apertures of the first pattern and theapertures of the second pattern along axes extending perpendicularlyfrom the first high mechanical strength layer to the second highmechanical strength layer. As shown in FIG. 2, separator system 100(2)comprises a first high mechanical strength layer 102(3) having a firstpattern comprising a plurality of apertures, e.g. 104(5) and 104(9), anda second high mechanical strength layer 102(4) having a second patterncomprising a second plurality of apertures, e.g. 104(6), 104(7) and104(8). First and second high mechanical strength layers 102 arecharacterized by lateral dimensions, such as height, H, length, L, andwidth or thickness, W. As shown in FIG. 1, apertures 104 extend entirelythrough the thickness of either first high mechanical strength layer102(3) or second high mechanical strength layer 102(4). Each aperture104 is also characterized by lateral dimensions, such as height, h,length, l, and width or thickness (not shown).

The superposition of the first pattern of first high mechanical strengthlayer 102(3) on the second high mechanical strength layer 102(4) isschematically presented as a plurality of dashed areas 106(3) on secondhigh mechanical strength layer 102(4), and the superposition of thesecond pattern of second high mechanical strength layer 102(4) on thefirst high mechanical strength layer 102(3) is schematically presentedas a plurality of dashed areas 106(4) on first layer 102(3). In theembodiment shown in FIG. 2, the first and second patterns have off-setalignments relative to one another such that there is a selected overlapof apertures 104 along axes extending perpendicularly from first highmechanical strength layer 102(3) to second high mechanical strengthlayer 102(4). In an embodiment, for example, the selected overlap isless than or equal to 50%, 40%, 30%, 20%, 10%, 5%, or 2%. In theembodiment shown in FIG. 2, the overlap of the apertures of the firstpattern and the apertures of the second pattern along axes extendingperpendicularly from the first high mechanical strength layer to thesecond high mechanical strength layer is greater than zero. The arrowsshown in FIG. 2 are provided so as to illustrate the overlapping regions112 of the apertures and regions of the apertures that do not overlapalong axis extending perpendicularly from first high mechanical strengthlayer 102(3) to second high mechanical strength layer 102(4). Theoff-set alignment of the pattern of apertures of the first highmechanical strength layer and the pattern of apertures of the secondhigh mechanical strength layer prevents growth of dendrites through thecombination of the first and second high mechanical strength layers, forexample, by blocking dendrite growth and/or requiring a pathwayinvolving curved trajectories which are thermodynamically and/orkinetically unfavorable.

The invention may be further understood by the following non-limitingexamples.

Example 1 Novel Separators for Electrochemical and Chemical Systems,Such as for Batteries, Such as for Rechargeable Lithium Batteries andEspecially to Prevent Dendrite Short Circuits in Li-Metal Batteries

FIG. 3 provides a schematic diagram illustrating a cross sectional viewof a multilayer separator system of the invention having first andsecond high mechanical strength layers (layers R and F) havingcomplementary patterns of apertures separated by anelectrolyte-containing layer (layer M). FIG. 4 provides a schematicdiagram illustrating a cross sectional view of a multilayer separatorsystem of the invention having first, second and third high mechanicalstrength layers (layers R and F) with complementary patterns ofapertures separated by electrolyte-containing layers (layer M). In FIGS.3 and 4, layers (R) and layers (F) are high mechanical strength layershaving patterns of apertures that when provided in combination preventdendrite growth through the separator system, for example, whenincorporated into an electrochemical system, such as an electrochemicalcell. In FIGS. 3 and 4, electrolyte-containing layer(s) M is providedbetween layers F and R and, in some embodiments, electrolyte-containinglayer(s) M is preferably thicker than layers F and R. In anelectrochemical system, for example, layer(s) M acts as a reservoir foran electrolyte. In an electrochemical system, for example, layer(s) Macts as a separator, thereby, preventing electrical and/or physicalcontact between the positive electrode and negative electrode whileallowing ion transport between positive and negative electrodes so thatthe electrochemical cell can undergo efficient discharge and chargingcharacteristics. In an embodiment, for example, layer M is a low ionicresistance layer, such as a conductive microporous membrane. In anembodiment, for example, layer M is a polyethylene (PE) membrane or apolypropylene (PP) membrane or a combination of both.

In some embodiments, high mechanical strength layers F and R function toprevent dendrite growth in an electrochemical cell such to preventelectrical shorting, thermal runaway and/or mechanical failure of thecell. As an example, high mechanical strength layers F and R may beconfigured to prevent the short circuit and capacity losses in lithiummetal batteries by preventing dendrite growth between positive andnegative electrodes. In some embodiments, high mechanical strengthlayers F and R provide complementary barriers each having a mechanicalstrength sufficient to prevent piercing or mechanical failure of thebarrier when in contact with a growing dendrite.

In some embodiments, high mechanical strength layers F and R areprovided with complementary patterns of apertures extending through theentire thickness of the layers. FIG. 5 provides a schematic diagramillustrating a cross sectional view of a multilayer separator system ofthe invention illustrating apertures (schematically illustrated as thedotted regions) and solid regions (schematically illustrated as thefilled regions) of the first and second high mechanical strength layersseparated by one or more low ionic resistance layers, such as anelectrolyte-containing layer M. FIG. 6 provides a schematic diagramillustrating a cross sectional view of a multilayer separator system ofthe invention illustrating apertures and solid regions of the first,second and third high mechanical strength layers separated by one ormore low ionic resistance layers, such as an electrolyte-containinglayer M. As an example, high mechanical strength layer(s) F may becharacterized by a preselected first pattern of apertures and solidregions, and high mechanical strength layer(s) R may be characterized bya second preselected pattern of apertures and solid regions that isdifferent from that of high mechanical strength layer F. In anembodiment, for example, the two patterns are complementary such thateach of the high mechanical strength layers F and R have apertures(e.g., through-holes, nanopores, micropores, channels, etc.) that allowthe transport of ions and electrolyte from either side of the highmechanical strength layer, but alignment of high mechanical strengthlayers F and R in the multilayer separator system geometry providesapertures of high mechanical strength layer F to match the solid regionsof high mechanical strength layer R and the solid regions of highmechanical strength layer F to match the holes of high mechanicalstrength layer R, for example along axes extending perpendicularly fromthe high mechanical strength layer(s) R to high mechanical strengthlayer(s) F. In an embodiment, for example, the apertures of highmechanical strength layers F and R are off-set with respect to eachother such that no straight line can go through the holes of both layersF and R when they are provided in combination, for example in a parallelor concentric orientation. This spatial arrangement can be visualized,for example, by considering a periodic pattern, such as a chess boardhaving white and black squares, wherein the white squares correspond tothe apertures and wherein the black squares correspond to the solidregions of the high mechanical strength layer. In an example, highmechanical strength layer F can be in the format of a typical chessboard, and high mechanical strength layer R is in the format of areverse one, misplaced chess board, in which the white blocks(corresponding to the apertures) are in the place of black squares(solid part of layer F) and black blocks (corresponding to the solidregions) are in the place of white squares (holes of layer F). Thisoff-set alignment results in at least two high mechanical strengthlayers wherein all the holes are blocked by solid regions of aneighboring layer when provided in a multilayer geometry.

Placement of the low ionic resistance layer M (typical separator)between high mechanical strength layers F and R provides a separatorsystem which prevents the unwanted growth of dendrites extending throughthe separator system. In order to minimize the effect of the separatorsystem on the resistance of the cell, however, it is desirable for someembodiments to minimize the thickness of high mechanical strength layersF and R while at least maintaining a thickness that is necessary toprovide sufficient mechanical strength to block growing dendrites.

In an embodiment, for example, high mechanical strength layers F and Rare very thin (e.g., thickness less than or equal to 100 μm andoptionally for some embodiments thickness less than or equal to 20 μm)and, thus, can optionally be in the form of one or more coatings on thefront and/or back sides of the layer M. The volume fraction and surfacefraction of holes in high mechanical strength layers F and R areselected for a given application, and for some applications it ispreferable that at least a quarter, and optionally half, of thesurface-volume comprises apertures and the remainder comprisingimpermeable solid regions. In an embodiment, high mechanical strengthlayers F and R comprise materials that do not react with othercomponents of an electrochemical cell and are chemically resistant andthermally stable. In an embodiment, high mechanical strength layers Fand R comprise electronic insulators.

In specific embodiments useful for a lithium-metal battery, highmechanical strength layers F and R comprise a polyethylene membrane orpolyimide membrane or polyester membrane or polypropylene membrane orTeflon or a mixture of these materials having complementary patterns ofapertures allowing the passage of ions and electrolyte through theapertures but preventing the passage of electrical current directlybetween positive and negative electrodes of an electrochemical cell. Inan embodiment, for example, low ionic resistance layer M is a porouspolyethylene membrane or a porous polypropylene membrane or a mixture ofthese. In an embodiment, low ionic resistance layer M has a thicknessselected from the range of 10 nm to 200 μm, selected from the range of80 μm to 120 μm or selected from the range of 5 μm to 25 μm, and highmechanical strength layers F and R each independently have a thicknessselected from the range of 5 μm to 200 μm, selected from the range of 10μm to 30 μm or selected from the range of 5 μm to 30 μm. In anembodiment, high mechanical strength layers F and R have complementaryperiodic patterns of apertures and solid regions, wherein one or morelateral dimensions of the unit cell characterizing the apertures and/orsolid regions is, for example, selected over the range of 1 micrometerand 1 millimeter, preferably 10-30 micrometers for some applications.Smaller sizes of the lateral dimensions of the unit cell of theapertures, as small as 10 times the average aperture size of layer R,are preferred for some embodiments; but it is acknowledged that theremay be practical advantages of large apertures with respect tofabrication, so there can be a compromise in the selection of thephysical dimensions of the apertures.

As will be apparent to one of skill in the art, the composition,physical dimensions (e.g., thicknesses) and mechanical properties (e.g.,porosity) of the components of the separator systems may depend on thetype of electrochemical or chemical cells and/or application. In anembodiment, for example, separator systems for lead-acid batteries mayemploy thicker high mechanical strength layers having larger hole sizesthan in separator systems for lithium-metal batteries.

Other separator geometries, besides the described R-M-F and F-M-R-M-Fsystems shown in FIGS. 3 and 5, are also useful for some applications.As an example, the invention includes multilayer systems with 3, 4, 5,6, 7, 8, etc. high mechanical strength layers having patterns ofapertures selected to prevent dendrite growth. Multilayer systems havingmore than two high mechanical strength layers, such corresponding to theF-M-R-M-F system shown in FIGS. 4 and 6, are preferred for someapplications as they may be configured to efficiently prevent growth ofdendrites from positive to negative electrodes and yet the addedresistance to the cell can still be maintained low enough to provideuseful discharge and charging performance.

As an example, a high energy rechargeable lithium battery of theinvention comprises: (1) an anode comprising lithium metal orlithium-alloy or mixtures of lithium metal and/or lithium alloy or zincmetal or ZnO or zinc alloy or silicon and another material; (2) acathode; (3) a separator system of the invention disposed between theanode and the cathode; and (4) one or more electrolytes in ioniccommunication, optionally in physical contact, with the anode and thecathode via the separator. In an embodiment, for example, theelectrolyte is either solid, gel or liquid (e.g. a fluid). In someembodiments, the electrodes are solid materials or are semi-solidparticles (e.g., small solid particles in liquids) such as what is usedin semi-solid batteries or in flow batteries or in flow cells. The crosssectional geometry of the separator system can be a range of shapesincluding rectangular, circular, square, etc.

FIG. 7 provides a schematic diagram providing a cross sectional view ofa lithium battery of the invention comprising a separator system withtwo high mechanical strength layers having complementary patterns ofapertures. The electrochemical cell comprises an anode (e.g., lithiummetal) and cathode that are separated by a multilayer separator systemincluding an electrolyte reservoir. The multilayer separator comprisestwo high mechanical strength layers having complementary patterns ofapertures separated by a low ionic resistance layer such as anelectrolyte-containing separator and/or spacer. In addition, very porousmedia is provided between the high mechanical strength layers and theanode and cathode components. As shown in FIG. 7, the high mechanicalstrength layers have patterns comprising alternating apertures and solidregions (e.g., in FIG. 7 the filled-in regions correspond to solidregions of the high mechanical strength layer and dotted regionscorrespond to apertures extending through the high mechanical strengthlayer). In the embodiment shown, the high mechanical strength layershave complementary patterns of apertures capable of preventing growth ofdendrites between cathode and anode, wherein open regions (e.g.,apertures) of a first high mechanical strength layer correspond to solidregions of the second high mechanical strength layer along axesextending perpendicularly from the layers, as shown in FIG. 7.

FIGS. 8-10 provide examples of other embodiments of lithium batteriesillustrating additional device configurations and device components ofthe invention. FIG. 8 provides a schematic diagram providing a crosssectional view of a lithium battery of the invention comprising aseparator system with four high mechanical strength layers havingcomplementary patterns of apertures. In the device illustrated in FIG.8, high mechanical strength layer R is provided in direct physicalcontact with the anode and high mechanical strength L is provided indirect physical contact with the cathode. In the embodiment shown inFIG. 8, the two layers R have the same pattern of apertures and the twolayers F have the same pattern of apertures. Together the patterns inlayers R and F comprise complementary patterns that eliminate any directlinear pathway between the anode and the cathode along axis extendingperpendicularly from cathode to anode, thereby preventing dendritegrowth related shorting. In the embodiment shown in FIG. 8, a highmechanical strength layer R is provided in physical contact with theanode so as to allow ions to pass through layer R and interact with theanode surface; and a high mechanical strength layer F is provided inphysical contact with the cathode so as to allow ions to pass throughlayer F and interact with the cathode surface.

FIG. 9 provides a schematic diagram providing a cross sectional view ofan electrochemical cell of the invention comprising a separator systemwith three high mechanical strength layers having complementary patternsof apertures. In the device illustrated in FIG. 9, a very porous layer(e.g., porosity ≧80%) is provided between the high mechanical strengthlayer F and the anode and a very porous layer (e.g., porosity ≧80%) isprovided between high mechanical strength layer F and the cathode. Inthe device illustrated in FIG. 9, high mechanical strength layer R has apattern of apertures that is complementary to the pattern of aperturesof high mechanical strength layers F, and a porous layer (e.g., porosity≧50%) is provided between high mechanical strength layer R and the highmechanical strength layers F. In an embodiment, for example, the twohigh mechanical strength layers F are characterized by the same patternof apertures. In the embodiment shown in FIG. 9, the two layers F havethe same pattern of apertures. Together the patterns in layer R and thetwo layers F comprise complementary patterns that eliminate any directlinear pathway between the anode and the cathode along axis extendingperpendicularly from cathode to anode, thereby preventing dendritegrowth related shorting. In the embodiment shown in FIG. 9, a veryporous layer (e.g., porosity ≧80%) is provided in physical contact withthe anode so as to allow ions to pass through this porous layer andinteract with the anode surface; and a very porous layer (e.g., porosity≧80%) is provided in physical contact with the cathode so as to allowions to pass through this porous layer and interact with the cathodesurface.

FIG. 10A provides a schematic diagram providing a cross sectional viewof an electrochemical cell of the invention comprising a lithium metalanode, cathode and a separator system comprising three high mechanicalstrength layers having complementary patterns of apertures, two lowionic resistance layers, two electrolyte containing voids and a framecomponent. In some embodiments, for example, the frame layer(s) providesa means of physically integrating, attaching and/or mechanicallysupporting the components of the overall multilayer arrangement. In thelithium battery shown in FIG. 10, an electrolyte containing void isprovided between the anode and a first high mechanical strength layerhaving a pattern of apertures and an electrolyte containing void isprovided between the cathode and a second high mechanical strength layerhaving a pattern of apertures. In some embodiments, for example,incorporation of an electrolyte containing void between the electrodeand the high mechanical strength layer is useful to avoid reducing theelectrode surface area so as to access useful discharge and chargecharacteristics of the cell. In the device illustrated in FIG. 10, highmechanical strength layer R has a pattern of apertures that iscomplementary to the pattern of apertures of high mechanical strengthlayers F, and a low ionic resistance layer (e.g., porosity ≧50%) isprovided between high mechanical strength layer R and the highmechanical strength layers F.

FIG. 10B provides a schematic diagram providing a cross sectional viewof an electrochemical cell (e.g. useful for Li-air, Li-water batteries)having a separator with a protective solid electrolyte, wherein thesolid electrolyte conducts the desired ions (such as Li⁺) but isimpermeable to water, air, CO₂, contaminations and materials thatdeteriorate the performance of the electrochemical cell. Theelectrochemical cell comprises an anode, such as a lithium anode; acathode, such as a carbon-water cathode or carbon-air cathode; aseparator system comprising two high mechanical strength layers havingcomplementary patterns of apertures, three low ionic resistance layers,and a solid electrolyte layer, such as a LISICON layer. In the deviceillustrated in FIG. 10B, the high mechanical strength layers areoptionally chemically resistant and thermally stable perforated layersthat are also electronically insulating, such as perforated Kaptonlayers. Use of complementary high mechanical strength layers comprisingKapton is useful in some embodiments for preventing dendrite growth. Asshown in FIG. 10B, a first low ionic resistance layer, such as a veryporous layer (e.g., ≧80%), is provided between the anode and a firsthigh mechanical strength layer and a second low ionic resistance layer,such as a very porous layer (e.g., ≧80%), is provided between the firsthigh mechanical strength layer and a second high mechanical strengthlayer, and a third low ionic resistance layer, such as a very porouslayer (e.g., ≧80%), is provided between the second high mechanicalstrength layer and the cathode. As shown in FIG. 10B, a solidelectrolyte layer, such as a LISICON layer, is provided between thethird low ionic resistance layer and the cathode such that ions are ableto be transported to the cathode surface. In an embodiment, for example,the solid electrolyte layer is provided in physical contact with asurface of the cathode. In some embodiments, incorporation of the solidelectrolyte layer (e.g., LISICON layer) is useful to protect thecathode, for example, to protect against unwanted chemical reactionswith the cathode surface and components of the electrochemical cell,such as electrolyte components other than the solid electrolyte. In someembodiments, the solid electrolyte layer (e.g., LISICON layer) providesa chemical barrier layer separating a first side of the electrochemicalcell having a first electrolyte from a second side of theelectrochemical cell having a second electrolyte that is different fromthe first electrolyte. Embodiments of this aspect, therefore, mayprovide a means for integrating two separate electrolytes each tailoredspecifically for selected anode and cathode compositions.

FIG. 10C provides a schematic diagram providing a cross sectional viewof an electrochemical cell (e.g., useful for Li-air, Li-water batteries)having a separator with a protective solid electrolyte, wherein thesolid electrolyte conducts the desired ions (such as Li⁺) but isimpermeable to water, air, CO2, contaminations and materials thatdeteriorate the performance of the electrochemical cell. Theelectrochemical cell comprises a lithium anode; a cathode such as acarbon-water cathode or carbon-air cathode; a separator systemcomprising two high mechanical strength layers having complementarypatterns of apertures, three low ionic resistance layers; and a solidelectrolyte layer, such as a LISICON layer. The overall electrochemicalcell geometry in FIG. 10C is similar to that shown in FIG. 10B, whereina first low ionic resistance layer, such as a very porous layer (e.g.,≧80%), is provided between the anode and a first high mechanicalstrength layer and a second low ionic resistance layer, such as a veryporous layer (e.g., ≧80%), is provided between the first high mechanicalstrength layer and a second high mechanical strength layer, and a thirdlow ionic resistance layer, such as a very porous layer (e.g., ≧80%), isprovided between the second high mechanical strength layer and thecathode, and wherein a solid electrolyte layer, such as a LISICON layer,is provided between the third low ionic resistance layer and the cathodesuch that ions are able to be transported to the cathode surface. In theelectrochemical cell of FIG. 10C, however, the high mechanical strengthlayers are perforated metal layers having complementary patterns ofapertures that are useful in some embodiments for preventing dendritegrowth and reducing anode loss such as in mossy deposition. Similar tothe discussion in connection with FIG. 10B, incorporation of the solidelectrolyte layer (e.g., LISICON layer) is useful to protect thecathode, for example, to protect against unwanted chemical reactionswith the cathode surface and components of the electrochemical cell,such as electrolyte components other than the solid electrolyte. In someembodiments, the solid electrolyte layer (e.g., LISICON layer) providesa chemical barrier layer separating a first side of the electrochemicalcell having a first electrolyte from a second side of theelectrochemical cell having a second electrolyte that is different fromthe first electrolyte, and therefore, may provide a means forintegrating two separate electrolytes each tailored specifically forselected anode and cathode compositions.

FIG. 10D provides a schematic diagram providing a cross sectional viewof an electrochemical cell (e.g., useful for Li-Sulfur batteries) havingseparator with a protective solid electrolyte, wherein the solidelectrolyte conducts the desired ions (such as Li⁺) but is impermeableto particle passage between cathode and anode that deteriorate theperformance of the electrochemical cell. The electrochemical cellcomprises an anode such as a lithium anode; a cathode such as asulfur-based cathode; a separator system comprising two high mechanicalstrength layers having complementary patterns of apertures, three lowionic resistance layers; and a solid electrolyte layer, such as aLISICON layer. The overall electrochemical cell geometry in FIG. 10C issimilar to that shown in FIGS. 10B and 10C, wherein a first low ionicresistance layer, such as a very porous layer (e.g., ≧80%), is providedbetween the anode and a first high mechanical strength layer and asecond low ionic resistance layer, such as a very porous layer (e.g.,≧80%), is provided between the first high mechanical strength layer anda second high mechanical strength layer, and a third low ionicresistance layer, such as a very porous layer (e.g., ≧80%), is providedbetween the second high mechanical strength layer and the cathode, andwherein a solid electrolyte layer, such as a LISICON layer, is providedbetween the third low ionic resistance layer and the cathode such thations are able to be transported to the cathode surface. In theelectrochemical cell of FIG. 10D, however, the high mechanical strengthlayers are perforated metal layers having complementary patterns ofapertures and the cathode is optionally a sulfur-based cathode.Incorporation of high mechanical strength metal layers in the presentseparators are useful in some embodiments for preventing dendritegrowth, reducing anode loss such as in mossy deposition and stopping thepassage of cathode materials to the anode. Similar to the discussion inconnection with FIG. 10B, incorporation of the solid electrolyte layer(e.g., LISICON layer) is useful to protect the cathode, for example, toprotect against unwanted chemical reactions with the cathode surface andcomponents of the electrochemical cell, such as electrolyte componentsother than the solid electrolyte. In some embodiments, the solidelectrolyte layer (e.g., LISICON layer) provides a chemical barrierlayer separating a first side of the electrochemical cell having a firstelectrolyte from a second side of the electrochemical cell having asecond electrolyte that is different from the first electrolyte, and,therefore, may provide a means for integrating two separate electrolyteseach tailored specifically for selected anode and cathode compositions

FIG. 10E provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the conductiveside of the separator next to the anode reduces anode loss; e.g., bystopping the dendrite growth, reducing anode loss such as in mossydeposition and stop the passage of cathode materials to the anode uponcycling which breaks the electronic contact between anode particles andthe current collector and deteriorate the performance of theelectrochemical cell. For example, the conductive side next to thecathode increases the electronic conductivity of the cathode which canresult in longer life cycle, higher power and thicker cathode, andhigher energy cathode and thus a better electrochemical cell. Theelectrochemical cell comprises an anode, such as a lithium anode; acathode, such as a LiFePO₄, LiCoO₂ cathode; a separator systemcomprising two high mechanical strength layers having complementarypatterns of apertures, three low ionic resistance layers; and amechanically, chemically and heat resistant ionic conductive layer suchas a carbon black layer. The overall electrochemical cell geometry inFIG. 10C is similar to that shown in FIGS. 10B, 10C and 10D, wherein afirst low ionic resistance layer, such as a very porous layer (e.g.,≧80%), is provided between the anode and a first high mechanicalstrength layer and a second low ionic resistance layer, such as a veryporous layer (e.g., ≧80%), is provided between the first high mechanicalstrength layer and a second high mechanical strength layer, and a thirdlow ionic resistance layer, such as a very porous layer (e.g., ≧80%), isprovided between the second high mechanical strength layer and thecathode. In the electrochemical cell of FIG. 10D, however, a first highmechanical strength layer comprises a perforated metal layer and asecond high mechanical strength layer comprises a perforatedelectronically insulating layer, such as a perforated Kapton layer. Inthis embodiment, the perforated metal layer and the perforated Kaptonlayer have complementary patterns of apertures to prevent dendritegrowth. In addition, a mechanically, chemically and heat resistant ionicconductive carbon black layer is provided adjacent to, and optionally inelectrical contact and/or physical contact with, the cathode.

FIG. 10F provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the perforatedseparator plates and the porous layers act as a separator by providingelectronic insulation between the electrodes, yet providing ionicconnection between the electrodes via a fluid electrolyte (aqueous oraprotic). The electrochemical cell comprises an anode, such as asilicon, Li, Zn, ZnO, Graphite or LTO anode; a cathode, such as aLiFePO4, LiCoO2, Sulfur, or Ag cathode; and a separator systemcomprising two high mechanical strength layers having complementarypatterns of apertures and three low ionic resistance layers. As shown inFIG. 10F, a first low ionic resistance layer, such as a very porouslayer (e.g., ≧80%), is provided between the anode and a first highmechanical strength layer and a second low ionic resistance layer, suchas a very porous layer (e.g., ≧80%), is provided between the first highmechanical strength layer and a second high mechanical strength layer,and a third low ionic resistance layer, such as a very porous layer(e.g., ≧80%), is provided between the second high mechanical strengthlayer and the cathode. In the electrochemical cell of FIG. 10F, firstand second high mechanical strength layers independently comprise amechanically, chemically and heat resistant electronically insulatinglayers, such as perforated metal layers having one or more insulatingcoatings such as a PE or PP coating.

FIG. 10G provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein shape memoryeffect of the two high mechanical strength layers results in a very goodmechanical contact between the separator and the electrodes. Theelectrochemical cell comprises an anode, such as a silicon, Li, Zn, ZnO,Graphite or LTO anode; a cathode, such as a LiFePO4, LiCoO2, Sulfur, orAg cathode; and a separator system comprising two high mechanicalstrength layers having complementary patterns of apertures and three lowionic resistance layers. The overall electrochemical cell geometry inFIG. 10G is similar to that shown in FIG. 10F, wherein a first low ionicresistance layer, such as a very porous layer (e.g., ≧80%), is providedbetween the anode and a first high mechanical strength layer and asecond low ionic resistance layer, such as a very porous layer (e.g.,≧80%), is provided between the first high mechanical strength layer anda second high mechanical strength layer, and a third low ionicresistance layer, such as a very porous layer (e.g., ≧80%), is providedbetween the second high mechanical strength layer and the cathode. Inthe electrochemical cell of FIG. 10G, however, first and second highmechanical strength layers independently comprise a mechanically,chemically and heat resistant electronically insulating layersexhibiting a shape memory effect, such as perforated Nitnonol layersthat are optionally coated with PE or PP.

FIG. 10H provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the superelasticity and/or shape memory effect of the two high mechanicalstrength layers results in a very good mechanical contact between theseparator and the electrodes. In an embodiment, of this aspect forexample, enhanced electrical contact is provided between the solidelectrolyte and the cathode. The electrochemical cell comprises a anodesuch as a silicon, Li, Zn, ZnO, Graphite, or LTO anode; a cathode suchas a LiFePO₄, LiCoO₂, Sulfur, Ag, Carbon-Air, Carbon-Water cathode; aseparator system comprising two high mechanical strength layers havingcomplementary patterns of apertures, three low ionic resistance layers;and a solid electrolyte layer, such as a LISICON or PEO (polyethyleneoxide) layer. The overall electrochemical cell geometry in FIG. 10H issimilar to that shown in FIGS. 10B, 10C and 10D, wherein a first lowionic resistance layer, such as a very porous layer (e.g., ≧80%), isprovided between the anode and a first high mechanical strength layerand a second low ionic resistance layer, such as a very porous layer(e.g., ≧80%), is provided between the first high mechanical strengthlayer and a second high mechanical strength layer, and a third low ionicresistance layer, such as a very porous layer (e.g., ≧80%), is providedbetween the second high mechanical strength layer and the cathode, andwherein a solid electrolyte layer, such as a LISICON or PEO layer, isprovided between the third low ionic resistance layer and the cathodesuch that ions are able to be transported to the cathode surface. In theelectrochemical cell of FIG. 10H, however, the high mechanical strengthlayers are mechanically, chemically and heat resistant electronicallyinsulating layers with super-elasticity or shape memory effect such asperforated Nitonol layers that may optionally be coated with PE or PP.Similar to the discussion in connection with FIG. 10B, incorporation ofthe solid electrolyte layer (e.g., LISICON or PEO layer) is useful toprotect the cathode, for example, to protect against unwanted chemicalreactions with the cathode surface and components of the electrochemicalcell, such as electrolyte components other than the solid electrolyte.In some embodiments, the solid electrolyte layer (e.g., LISICON layer)provides a chemical barrier layer separating a first side of theelectrochemical cell having a first electrolyte from a second side ofthe electrochemical cell having a second electrolyte that is differentfrom the first electrolyte, and, therefore, may provide a means forintegrating two separate electrolytes each tailored specifically forselected anode and cathode compositions

FIG. 10I provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the superelasticity and/or shape memory effect of two high mechanical strengthlayers results in a very good mechanical contact between the separatorand the electrodes. In an embodiment of this aspect, for example,enhanced electrical contact is provided between the solid electrolyteand the cathode. The electrochemical cell comprises an anode such as asilicon, Li, Zn, ZnO, Graphite, or LTO anode; a cathode such as aLiFePO₄, LiCoO₂, Sulfur, Ag, Carbon-Air, Carbon-Water cathode; aseparator system comprising two high mechanical strength layers havingcomplementary patterns of apertures, three low ionic resistance layers;and a solid electrolyte layer, such as a LISICON or PEO layer. Theoverall electrochemical cell geometry in FIG. 10I is similar to thatshown in FIGS. 10B, 10C and 10D, wherein a first low ionic resistancelayer, such as a very porous layer (e.g., ≧80%), is provided between theanode and a first high mechanical strength layer and a second low ionicresistance layer, such as a very porous layer (e.g., ≧80%), is providedbetween the first high mechanical strength layer and a second highmechanical strength layer, and a third low ionic resistance layer, suchas a very porous layer (e.g., ≧80%), is provided between the second highmechanical strength layer and the cathode, and wherein a solidelectrolyte layer, such as a LISICON layer, is provided between thethird low ionic resistance layer and the cathode such that ions are ableto be transported to the cathode surface. In the electrochemical cell ofFIG. 10I, however, the high mechanical strength layers are mechanically,chemically and heat resistant electronically insulating layersexhibiting a super-elasticity and/or shape memory effect such as aperforated shape memory polymer layer. Similar to the discussion inconnection with FIG. 10B, incorporation of the solid electrolyte layer(e.g., LISICON or PEO layer) is useful to protect the cathode, forexample, to protect against unwanted chemical reactions with the cathodesurface and components of the electrochemical cell, such as electrolytecomponents other than the solid electrolyte. In some embodiments, thesolid electrolyte layer (e.g., LISICON or PEO layer) provides a chemicalbarrier layer separating a first side of the electrochemical cell havinga first electrolyte from a second side of the electrochemical cellhaving a second electrolyte that is different from the firstelectrolyte, and, therefore, may provide a means for integrating twoseparate electrolytes each tailored specifically for selected anode andcathode compositions.

FIG. 10J provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the conductiveside of the separator reduces anode loss such as in silicon largedeformations upon cycling which breaks the electronic contact betweenanode particles and the current collector and deteriorate theperformance of the electrochemical cell. The electrochemical cellcomprises an anode, such as a silicon anode; a cathode, such as aLiFePO₄ or LiCoO₂ cathode; and a separator system comprising two highmechanical strength layers having complementary patterns of aperturesand three low ionic resistance layers. The overall electrochemical cellgeometry in FIG. 10J is similar to that shown in FIG. 10F, wherein afirst low ionic resistance layer, such as a very porous layer (e.g.,≧80%), is provided between the anode and a first high mechanicalstrength layer and a second low ionic resistance layer, such as a veryporous layer (e.g., ≧80%), is provided between the first high mechanicalstrength layer and a second high mechanical strength layer, and a thirdlow ionic resistance layer, such as a very porous layer (e.g., ≧80%), isprovided between the second high mechanical strength layer and thecathode. In the electrochemical cell of FIG. 10J, however, the firsthigh mechanical strength layer comprises a mechanically, chemically andheat resistant ionically conductive and electrically conductive layerpositioned proximate to the anode, such as a perforated metal layer; andthe second high mechanical strength layer comprises a mechanically,chemically and heat resistant nonconductive perforated layer positionedproximate to the cathode, such as a perforated Kapton layer.

FIG. 10K provides a schematic diagram providing a cross sectional viewof an electrochemical cell having a separator wherein the conductiveside of the separator next to the anode reduces anode loss such as insilicon large deformations upon cycling which breaks the electroniccontact between anode particles and the current collector anddeteriorate the performance of the electrochemical cell. In anembodiment of this aspect, the conductive side next to the cathodeincreases the electronic conductivity of the cathode which can result inlonger life cycle, higher power and thicker cathode, and higher energycathode and thus a better electrochemical cell. The electrochemical cellcomprises an anode, such as a silicon anode; a cathode, such as aLiFePO₄ or LiCoO₂ cathode; and a separator system comprising three highmechanical strength layers having complementary patterns of aperturesand three low ionic resistance layers. As shown in FIG. 10K a first lowionic resistance layer, such as a very porous layer (e.g., ≧80%), isprovided between the anode and a first high mechanical strength layer, asecond low ionic resistance layer, such as a very porous layer (e.g.,≧80%), is provided between the first high mechanical strength layer anda second high mechanical strength layer, a third low ionic resistancelayer, such as a very porous layer (e.g., ≧80%), is provided between thesecond and third high mechanical strength layers. In the electrochemicalcell of FIG. 10K, the first and third high mechanical strength layerspositioned proximate to anode and cathode, respectively, comprises amechanically, chemically and heat resistant layers, such as a perforatedmetal layers; and the second high mechanical strength layer providebetween the first and second high mechanical strength layers comprises amechanically, chemically and heat resistant electronically insulatingand ionically conductive layer, such as a perforated Kapton layer.

FIG. 10L provides a schematic diagram providing a cross sectional viewof an electrochemical cell embodiment having a mechanically, chemicallyand/or heat resistant layer that is ionically and electronicallyconductive positioned adjacent to the cathode. The electrochemical cellof this embodiment comprises an anode, such as a silicon anode; acathode, such as a LiFePO₄ or LiCoO₂; and a series of layers including apair of very porous layers, such as 80% porous PE layers, amechanically, chemically, and/or heat resistant layer that iselectronically and ionically conductive, such as carbon black, and amechanically, chemically and/or heat resistant layer that is ionicallyconductive but electronically insulating, e.g., PE, PP or perforatedKapton. The use of a mechanically, chemically and/or heat resistantlayer that is ionically and electronically conductive positionedadjacent to the positive electrode permits use of cathode materials thatexpand and contract during charging/discharging, as a secondaryconductivity path for current collection is provided by this layer whichmay route electrons to the cathode current collector.

FIG. 10M provides a schematic diagram providing a cross sectional viewof an electrochemical cell embodiment. The electrochemical cell of thisembodiment comprises an anode, such as a silicon, Li, zinc, zinc-oxide,LTO, graphite, Na, Mg, Sn, Cd, Pb or PbO₂ anode; a cathode, such as aLiFePO₄, LiCoO₂, sulfur, FeS, V₂O₅, LVO, Carbon-air, carbon-water,silver, silver oxide, Ni, Pb, PbO₂ or carbon; a mechanically,chemically, and/or heat resistant separator layer that is ionicallyconductive but electronically insulating, such as PE, PP, Kapton orfibrous cellulose; and a pair of thin electronically conductivecoatings, that are optionally provided on the cathode surface, the anodesurface and/or an outside surface of the separator, such as a 5 nm layerof carbon black. The use of thin electronically conductive coatingadjacent to one or both electrodes enables a secondary conductivity pathfor current collection by this layer which may route electrons to thecathode or anode current collector. The conductive layer on the outsideof the electrode reduces capacity loss such as in silicon where largedeformations upon cycling can break the electronic contact betweenelectrode active particles and the current collector and deteriorate theperformance of the electrochemical cell. At the same time, theconductive coating (such as nanometers thick carbon black) is ionicconductive and allows easy passage of ions, such as Li ions.

FIG. 10N provides a schematic diagram providing a cross sectional viewof an electrochemical cell embodiment. The electrochemical cell of thisembodiment comprises an anode, such as lithium; one or more porouslayers, such as 80% porous PE; a mechanically, chemically, and/or heatresistant layer that is electronically and ionically conductive, such asa perforated metal; a mechanically, chemically and/or heat resistantlayer that is ionically conductive but electronically insulating, suchas a perforated Kapton layer; a mechanically, chemically and/or heatresistant layer that is electronically and ionically conductive, such ascarbon black; and a cathode, such as LiFePO₄ or LiCoO₂. The conductivematerial proximate to the anode reduces anode loss, for example, bystopping the dendrite growth, reducing anode loss such as in mossydeposition and stopping the passage of cathode materials to the anodeupon cycling which breaks the electronic contact between anode particlesand the current collector, thus deteriorating the performance of theelectrochemical cell. The conductive material proximate to the cathodeincreases the electronic conductivity of the cathode which can result inlonger life cycle, higher power and thicker cathode, and higher energycathode and, thus, a better electrochemical cell.

FIG. 10O provides a schematic diagram providing a cross sectional viewof an electrochemical cell embodiment. The electrochemical cell of thisembodiment comprises an anode, such as silicon; one or more porouslayers, such as 80% porous PE; at least mechanically, chemically, and/orheat resistant layer that is electronically and ionically conductive,such as a perforated metal, positioned proximate to the anode and acathode, optionally spaced by a porous layer; a mechanically, chemicallyand/or heat resistant layer that is ionically conductive butelectronically insulating, such as a perforated Kapton layer; and acathode, such as LiFePO₄ or LiCoO₂. The conductive material proximatethe anode reduces anode loss, such as in silicon, where largedeformations upon cycling breaks the electronic contact between anodeparticles and the current collector and deteriorates the performance ofthe electrochemical cell. The conductive side proximate to the cathodeincreases the electronic conductivity of the cathode which can result inlonger life cycle, higher power and thicker cathode, and higher energycathode and thus a better electrochemical cell.

FIG. 10P provides a schematic diagram providing a cross sectional viewof an electrochemical cell embodiment. The electrochemical cell of thisembodiment comprises an anode, such as silicon; one or more porouslayers, such as 80% porous PE; at least two a mechanically, chemically,and/or heat resistant layers that are electronically and ionicallyconductive, such as a carbon black; a mechanically, chemically and/orheat resistant layer that is ionically conductive but electronicallyinsulating, such as a perforated Kapton layer; and a cathode, such asLiFePO₄ or LiCoO₂. The conductive material proximate the anode reducesanode loss, such as in silicon, where large deformations upon cyclingbreaks the electronic contact between anode particles and the currentcollector and deteriorates the performance of the electrochemical cell.The conductive side proximate to the cathode increases the electronicconductivity of the cathode which can result in longer life cycle,higher power and thicker cathode, and higher energy cathode and thus abetter electrochemical cell.

FIGS. 11A and 11B provide examples of the designs of porous, patternedlayers of the some separator systems of the invention, such as layers Fin FIGS. 2-10. In the embodiments shown in FIGS. 11A and 11B, forexample, there are alternating porous regions (schematically shown asdotted regions) and solid regions (schematically shown as filled-inregions). In these embodiments, the layer(s) R may provide the reversepatterned of apertures of the designs of the layers F. In FIGS. 11A and11B, the pattern is characterized by alternating rectangular porousregions and solid regions. Optionally, the apertures of some of thelayers F or R are filled with a solid or gel electrolyte.

Example 2 High Performance Inexpensive Rechargeable Lithium Batteries:Engineering the Separator and Electrodes

The highest energy batteries known so far use metals such as zinc andlithium, which are inexpensive, and have very high energy/powerdensities. Meanwhile, recharging these batteries poses major safetyhazards. A requirement for mitigating the safety problems is very strongyet highly conductive separators that can resist dendrite formation,accidents and thermal runaway.

Using engineering methods in building separators and electrodes, theseparator systems of this example provide a significant improvement ofsafety, durability, power and energy performance in a variety of batterychemistries. One approach of the invention is to apply engineeringknowledge and methods to the most efficient chemistries used in thebattery industry. As shown in this example, the invention providesmanufacturing friendly methods to make ultra-safe, high-capacityseparators. Coin cells tests made of commercial lithium metal, LiFePO₄and the present separator systems demonstrate the separatorconductivities are comparable to conventional Celgard separators, themechanical strength of solids and a working temperature range of −40 to200 Celsius. The separator systems of this example can be an essentialpart of Li-ion based super capacitors, Li-ion based flow batteries,Li-Sulfur, Li-air, Li-water, Zn batteries, Manganese batteries, Siliconanode batteries or Zn-air batteries.

A goal of certain aspects of the invention is to enhancerechargeability, safety and high cycle life of the existingnon-rechargeable high-energy chemistries such as lithium metal and zincbatteries and silicon anode batteries and air cathode batteries and flowbatteries and provide advanced electrochemical systems for high-energyrechargeable metal-air batteries which provide economic solutions toenergy storage challenges, especially in utility-scale batteries.

Current state of the art lithium metal batteries are not rechargeable,mostly due to dendrite formation which may result in internal shorts andin fires and explosions. At the same time, silicon as a potentialhigh-energy anode undergoes very large shape changes and loses itselectronic contact with the current collector, unless one uses veryexpensive nano-silicone grown carefully in preferred directions (notscalable). Many different electrolytes and additives have been testedand failed to be useful in an industrial level system. Recently, varioussolid electrolytes have been introduced to enhance the safety, but theyhave orders of magnitude lower conductivity compared to liquidelectrolyte-separator systems, and lose their performance after very fewcycles due to fatigue, cracks and lost electrode-electrolyte contacts.

Using a novel and scalable process, aspects of the invention providehighly porous separator systems (e.g., greater than or equal to than10⁻² S/cm conductivity with liquid electrolyte, at room temperature)with mechanically rigid materials (e.g., more than 1 GPa elasticmodulus, and temperature range of −200 to 400 Celsius) that resist thegrowth of dendrites. Embodiments of the present separator systemsprovide a new device architecture that enables high-energy, low-costutility-scale batteries for a variety of chemistries. Embodiments of thepresent separator systems also provide accident safe transportationbatteries. Experimental results indicate, for example, batteriesintegrating the present separator systems may achieve more than 5,000cycles with no or minimal capacity loss. In addition, some of theseparator systems are able to be readily implemented into casting androll-to-roll processing methodologies, already used in current lithiumbattery manufacturing.

An important feature of certain embodiments of the invention is amultilayer separator system that provides high conductivity and highsafety at the same time. FIG. 12 provides a schematic diagram of a crosssectional view of an electrochemical cell including a separator systemof the invention. As shown in FIG. 12, the electrochemical cellcomprises anode (3) and cathode (4) separated from each other by aseparator system (5). In this embodiment, the separator system (5)comprises a plurality of layers including perforated layers (1 and 1′)comprising a strong material and having a pattern of apertures and frameand/or very porous layers (2). The high elastic modulus of theperforated layers of the separator material prevents dendrites fromdirectly piercing the barrier. FIG. 14 provides examples of patterns ofapertures useful in the perforated layers of separator systems of theinvention. As shown in FIG. 14, perforated layers of the separatorsystems may have apertures with circular or rectangular shapes. FIG. 14also illustrates complementary patterns for perforated layers useful forpreventing dendrite growth, shorting and mechanical failure. Forexample, panels A and B provide complementary patterns of apertureswhich do not overlap when provided in the off-set alignment of certainseparator systems. Panel C provides a schematic illustrating thesuperposition of the patterns in panels A and B showing that the off-setalignment results in no overlap of the apertures. Similarly, panels Fand G provide complementary patterns of apertures which do not overlapwhen provided in the off-set alignment of certain separator systems.Similarly, panels H and I provide complementary patterns of apertureswhich do not overlap when provided in the off-set alignment of certainseparator systems. Similarly, panels J and K provide complementarypatterns of apertures which do not overlap when provided in the off-setalignment of certain separator systems. Similarly, panels L and Mprovide complementary patterns of rectangular apertures which do notoverlap when provided in the off-set alignment of certain separatorsystems.

The large number of apertures in the perforated layer ensures highconductivity of the separator and the offset alignment of the pores inthe successive layers ensures that there is no direct path between theelectrodes. The force from the high mechanical strength layers on thedendrites slows down or stops the dendrite growth. In an electrochemicalcell this significantly improves the performance of the cell. FIG. 13provides a schematic diagram illustrating a required trajectory ofdendrite growth to make a short in an electrochemical system of theinvention. In this figure, the dendrite is shown as a curved lineextending from anode to cathode. As shown in FIG. 13, dendrites wouldhave to make several curvatures to pass through the perforated layersand create a short. From a strictly mechanical view, the elastic modulusof lithium (5 GPa) is too high to allow successive curvatures ofdendrites in a small length (less than 0.1 mm); the required energy tobend a straight beam is U=∫₀ ^(l)EI/R²dx, where E is the elasticmodulus, I is the moment of inertia, and R(x) is the radius of thecurvature at each point, finally, L is the length of the element. From achemical engineering standpoint, the dendrites have too much kineticfrustration to overcome such a convoluted growth path. Additionally, theresistive pressure of the solid components of the high mechanicalstrength layers slows down and can even stop dendrite growth. Thelayered separator system including perforated layers havingcomplementary patterns of apertures effectively prevents dendrite growthand therefore prevents shorts. The materials and fabrication methodsnecessary for such a composite separator system are compatible with thepresent battery fabrication infrastructure, allowing low-costimplementation into current battery manufacturing. The inventionprovides cost-effective, safe and high-energy lithium batteries wellsuited for load leveling in a power grid with very slow charging (e.g.,C/10) and very fast discharging (e.g., 4C). The invention also providesa process of making layered separators resulting in industriallyfriendly batteries characterized by the conductivity of liquidelectrolytes, the safety of solid electrolytes, high cycle life and lowcost. Optionally, in some embodiments this is achieved by layers made ofshape memory materials such as Nitonol or shape memory polymers.Applying pre-stress such as in-plane tension on the shape memory layerof separator, will cause out of plane pressure on the electrodes whenthe layer is put in the cell. This can be especially useful in largerbattery cells such as 18650 cylindrical cells or wound cells.

The electrochemical systems of the invention are also compatible withthe use of engineered electrodes such as pre-stressed electrodes.Lithium metal when compressed in an out-of-plane direction performssignificantly better by leveling its surface (less mossy and lessdendrites). Also, out-of-plane compression in silicon anodes results inmuch better contacts with the current collectors and much higher lifecycle. This aspect of the invention can also be helpful in solid statebatteries by maintaining a good contact between the electrodes and thesolid electrolyte and increasing the cycle life and performance.Optionally, in some embodiments this is achieved by layers made of shapememory materials such as Nitonol or shape memory polymers. Applyingpre-stress such as in-plane tension on the shape memory layer ofseparator, will cause out of plane pressure on the electrodes when thelayer is put in the cell. This can be especially useful in largerbattery cells such as 18650 cylindrical cells or wound cells.

To further demonstrate the beneficial attributes of the presentinvention, over 100 coin-cells incorporating a composite layer separatorsystem have been made and evaluated. Some of the tested separators arecurrently 0.125 mm thick and keep 75% capacity at C/2 compared to 0.025mm Celgard. Safety tests including high current cycling, 55 mA/cm2 for300 cycles, show that the separator system is robust and the batterydoes not internally short. Furthermore, there is no measurabledegradation or capacity loss after several hundred cycles, in contrastto 5-layer Celgard separators (0.125 mm thick) which were completelydestroyed. The invention includes separator systems optionally having anoverall thickness of 0.075 mm. The invention optionally includes 0.025mm thick rolls of the separator system useful for 10 kWh packs ofcylindrical 18650 lithium metal batteries with 400 Wh/kg energy and 5000cycles.

Grid level energy storage is currently dominated by pumped hydro, over99% of current storage, which is only possible at a very few limitedsites and applications, is not suitable for society's growing storageneeds. Other solutions have significant shortcomings. Compressed airtechnology suffers from very low round trip efficiency of less than 20%.Electrochemical capacitors and flywheels have very low energy/costratios. Flow batteries, used as a combination of high-power andhigh-energy, are very complicated and expensive. Current batteries alsosuffer from high cost/energy and cost/power ratios (at about $1/Wh). Thestate-of-the-art high energy lithium-metal, metal-air, and nano-siliconchemistries have major safety/cost problems as mentioned earlier.

In some embodiments, the separator-electrodes design of the inventionenables a range of rechargeable high-energy chemistries that arecurrently not considered safe and/or have short cycle life. Usingindustrial methods of manufacturing (e.g., CNC, molding, casting) theinvention combines electrochemistry with engineering to address safetyissues with state of the art battery technologies. The present separatorsystems combined with high-energy electrodes, provide safe, long cyclelife, high energy batteries at industrial scale for grid storage andalso electric vehicles.

The present systems and methods are scalable and industrially friendly.Enhancing separator performance may be achieved via several approachesamenable with the present systems and methods. Improving theconductivity by making smaller holes (0.010 to 0.100 mm) and usingthinner layers (0.005 mm) are useful approaches for accessing highperformance systems. In addition, maintaining the required offsetalignment and attaching the layers by thermal heating at the boundariesand other selected areas may be used to access separator systemsproviding enhanced safety.

FIG. 15 provides a plot of charge and discharge capacities (mAh/g) as afunction of number of cycles for an electrochemical cell having: (A) amultilayer separator system of the invention having an overall thicknessof 125 microns and (B) a Celgard separator having a thickness of 25microns. The CR2032 coincell evaluated is made of Li foil 0.5 mm thickanode, LiFePO4 (0.0142 g) cathode, 1M LiPF6 in EC:DEC:DMC (1:1:1). Thevoltage limits are 3 v (discharge) and 4 v (charge). Formation, 3 cyclesat C/5, and the C/2 cycling are distinguishable from the sharp drop inthe capacity. The top line shows a separator made with two perforatedKapton layers as mechanical strong layers and 3 perforated Celgard 2325layers as low resistance layers. The bottom line shows a separator madewith two perforated Kapton layers as mechanical strong layers and 3Celgard 2325 layers as low resistance layers. The cells are tested inroom temperature. No measurable capacity drop was observed after 40-50cycles. The experimental results shown in FIG. 15 indicate that thepresent separators provide low resistance, and thus, are compatible witha range of electrochemical systems.

FIG. 16 provides a plot of charge and discharge capacities (mAh/g) as afunction of number of cycles for: (A) an electrochemical cell having amultilayer separator system of the invention, a Li metal anode and aLiCoO₂ cathode as compared to (B) an electrochemical cell having aconventional separator. The electrochemical cells were coin cells andevaluated at a discharge rate of C/2. The CR2032 coincell evaluated ismade of Li foil, 0.5 mm thick anode, LiCoO₂, 0.1 mm thick cathode, 1MLiPF6 in EC:DEC:DMC (1:1:1). The voltage limits are 3 v (discharge) and4.2 v (charge). Formation, 5 cycles at C/24, and the C/2 cycling aredistinguishable from the sharp drop in the capacity. The red lines(indicated by the letter B), 1, 5, 6 show cells made with a separatormade with two perforated Kapton layers (2 mm diameter holes) asmechanical strong layers and 3 Celgard 2325 layers as low resistancelayers. The blue lines (indicated by the letter A), 2, 3 show areference electrode made with a perforated Kapton between two Celgardlayers. The cells are tested in room temperature. The cells were cycledat C/2 and then were cycled at C/24 for a few cycles and then again atC/2. The experimental results show that the capacity loss was not due toany chemical reactions in the cell, and were likely due to theresistance of the perforated Kapton layers in the electrochemical cellsevaluated. FIG. 16 shows that using other materials, surface treatmentsor a homogenous distribution of holes, and thus smaller holes, arenecessary to reach a good capacity in the cell under some experimentalconditions.

FIG. 17 provides a plot of charge and discharge capacities (mAh/g) as afunction of number of cycles for: (i) an electrochemical cell having amultilayer separator system of the invention, a Li metal anode and aLiFePO₄ cathode as compared to (ii) an electrochemical cell having 3conventional separators having a thickness of 75 microns and (iii) aCelgard separator having a thickness of 25 microns. The electrochemicalcells were coin cells and evaluated at a discharge rate of C/2. TheCR2032 coincell evaluated is made of Li foil, 0.5 mm thick anode,LiFePO4, 0.1 mm thick cathode, 1M LiPF6 in EC:DEC:DMC (1:1:1). Thevoltage limits are 3 v (discharge) and 4 v (charge). Formation, 5 cyclesat C/24, and the C/2 cycling are distinguishable from the sharp drop inthe capacity. The lines I, H show cells made with single Celgard layers.The lines, A, B, C, show cells with a separator made with two perforatedKapton layers as mechanical strong layers and 3 Celgard 2325 layers aslow resistance layers. The lines F and D show a reference electrode madewith a perforated Kapton between two Celgard layers. The cells aretested in room temperature. The test demonstrates the importance ofhaving thin separators to reach high capacity in the cells.

FIG. 18 provides a schematic diagram illustrating an electrochemicalcell of the invention having a multilayer separator comprising threehigh mechanical strength layers with complementary patterns ofapertures, an anode and a cathode. FIG. 19 provides a schematic diagramillustrating the trajectory of Li⁺ ions passing through the multilayerseparator shown in FIG. 18. While Li⁺ ions are able to efficiently passthrough the multilayer separator as shown in FIG. 19, dendrites are notable to make the same trajectory and, thus are prevented in certainembodiments of the invention. Further, the force from the highmechanical strength layers slows down or even stops the dendrite growth.

FIG. 20 provides a plot of cell voltage (V vs Li) versus cycling time(h) for the galvanostatic lithium stripping from two symmetrical ( 5/9)″lithium chips with a multilayer separator of the present invention.Layers of a novel separator (0.125 mm thick) made with 2 Kapton layersas the high strength layers and 3 Celgard layers next to them as lowresistance layers in a CR2032 cell. Celgard 2325 is used. The cells aremade with 0.75 mm Li foils as electrodes and 1M LiPF6 in EC:DEC:DMC(1:1:1) from Novolte, as electrolyte. The Kapton holes are each 1 mmdiameter. Cells are tested at room in an Argon-filled dry box (H₂O<0.1ppm). This figure shows that the multilayered separator can safely stopdendrite shorting and prevent catastrophic failure even at very highcurrents.

FIG. 22 shows the current [amper] vs. time [s] (top plot) and voltage[v] vs. time [s] (bottom plot) for the experiment of FIG. 15. This showsthe top red line.

FIGS. 23-30 provide photographs of perforated layers useful in separatorsystems of some embodiments. FIG. 23, for example, provides pictures ofthe different separator materials (5-Celgard separator: A) and newseparator B)-D) after cycling a few days at high current: A) 5-Celgardseparator (from top-left to bottom-right: Li+Celgard, Li+Celgard,Stainless steel current collector; A typical separator (Celgard)punctured by lithium dendrites and destroyed. As can be seen theseparator is not recognizable anymore B) Celgard layer between the twoperforated Kapton layers; C) Celgard in contact with the lithiumelectrode; D) perforated Kapton. Lithium dendrites could not penetratethe new separator. Shown here, a Kapton layer of the new separator isintact, though the Celgard on the right side of the Kapton layer isdestroyed. FIGS. 25-30, for example, are pictures of a 1 mil kapton filmprepared with laser cutting for use in a separator system of theinvention.

FIG. 23 shows the layers of a novel separator (0.125 mm thick) made with2 Kapton layers as the high strength layers and 3 Celgard layers next tothem as low resistance layers in comparison with 5 Celgard layers (0.125mm thick) as a reference separator in a house made cell of ½″ diameter.Celgard 2325 is used. The cells are made with 0.75 mm Li foils aselectrodes and 1M LiPF6 in EC:DEC:DMC (1:1:1) from Novolte, aselectrolyte. The Kapton holes are each 2 mm diameter. Cells are testedat room temperature and are cycled at 55 mA for 45 minutecharge-discharge cycles in an Argon-filled dry box (H₂O<0.5 ppm) (A)Reference separator: shows 5-Celgard reference separator: the cell isshorted; (B-D) show components of the new separator. The cell is notshorted. (B) new separator: Celgard layer between the two perforatedKapton layers is intact; (C) New separator: Celgard in contact with thelithium electrode shows severe damage; (D) new separator: perforatedKapton is intact and maintains its structural integrity, preventing anyshort. This figure shows that the multilayered separator can safely stopdendrite shorting and prevent catastrophic failure even at very highcurrents. FIG. 24 (zoom out) is the same as FIG. 23 (zoom in). The topand bottom graphs show two adjacent layers in each design. FIG. 25-30show several examples of the strong layer design made of Kapton. Theholes are made with Laser cutting. The size of each of the layers is ½inch. The holes are either 1 mm diameter or 2 mm diameter.

Example 3 Lithium Batteries Having a Multilayer Separator System

This Example provides description of examples of lithium batteriescomprising a multilayer separator system of the present invention.

Example A: In this example, two layers of Kapton films, each 25micrometers thick, are used for the separator system. Each layer isperforated with Cartesian (vertical-horizontal) periodic holes, each 1mm diameter, and with 1 mm distance between the walls. A layer ofCelgard 25 micrometers is placed in between the two Kapton layers. Alayer of Celgard 25 micrometers is placed in between each Kapton layerand the adjacent electrode. The electrodes are LiCoO₂ and Lithium metalfilms. The electrolyte is LiPF₆ in a combination of EC-DMC-PC-DME.

Example B: In this example, two layers of Kapton films, each 25micrometers thick, are used for the separator system. Each layer isperforated with Cartesian (vertical-horizontal) periodic holes, each 1mm diameter, and with 1 mm distance between the walls are used for theseparator system. A layer of Celgard, 25 micrometers, is placed inbetween the two Kapton layers. A layer of Celgard 25 micrometers isplaced in between each Kapton layer and the adjacent electrode. Theelectrodes are LiFePO₄ and Lithium metal films. The electrolyte is LiPF₆in a combination of EC-DMC-PC-DME.

Example C: In this example, two layers of Kapton films, each 25micrometers thick, are used for the separator system. Each layer isperforated with Cartesian (vertical-horizontal) periodic holes, each 1mm diameter, and with 1 mm distance between the walls are used for theseparator system. A layer of perforated Celgard, 25 micrometers thickwith 3 holes each ⅛ inch, is placed in between the two Kapton layers. Alayer of perforated Celgard, 25 micrometers thick with 3 holes each ⅛inch, is placed in between each Kapton layer and the adjacent electrode.The electrodes are LiFePO₄ and Lithium metal films. The electrolyteLiPF₆ in is a combination of EC-DMC-PC-DME.

Example D: In this example, two layers of PP films, each 25 micrometersthick and ¾ inch diameter, are used for the separator system. Each layeris perforated with Cartesian (vertical-horizontal) periodic holes, each1 mm diameter, and with 1 mm distance between the walls. A ring ofCelgard, 25 micrometers thick, is placed in between the two PP layers. Aring of Celgard, 25 micrometers thick and ¾ inch outside diameter and ½inch inside diameter, is placed in between each PP layer and theadjacent electrode. The electrodes are LiFePO₄ and Lithium metal films.The electrolyte is LiPF₆ in a combination of EC-DMC-PC-DME.

Example E: In this example, two layers of hard polyester films, each 5micrometers thick and ¾ inch diameter, are used for the separatorsystem. Each layer is perforated with Cartesian (vertical-horizontal)periodic holes, each 1 mm diameter, and with 1 mm distance between thewalls. A ring of microporous PE/PP/PE, 5 micrometers thick, is placed inbetween the two hard polyester layers. A ring of microporous PE/PP/PE, 5micrometers thick and ¾ inch outside diameter and ½ inch insidediameter, is placed in between each hard polyester layer and theadjacent electrode. The electrodes are LiFePO₄ and Lithium metal films.The electrolyte is LiPF₆ in a combination of EC-DMC-PC-DME.

Example F: In this example, two layers of stainless steel, each 5micrometers thick, are used. The steel layers are coated with a verythin electronically isolating layer (here 1 micrometer thick Teflon.Kapton or PVDF or PEO or PP or PE coatings can also be used). Each layeris perforated with Cartesian (vertical-horizontal) periodic holes, each0.5 mm diameter, and with 0.5 mm distance between the walls. A layer ofmicroporous PE/PP/PE, 5 micrometers, is placed in between the twostainless steel layers. A layer of microporous PE/PP/PE 5 micrometers isplaced in between each stainless steel layer and the adjacent electrode.The electrodes are LiFePO₄ and Lithium metal films. The electrolyte isLiPF₆ in a combination of EC-DMC-PC-DME.

Example G: In this example, two layers of Kapton films, each 5micrometers thick and ¾ inch diameter, are used for the separatorsystem. Each layer is perforated with Cartesian (vertical-horizontal)periodic holes, each 1 mm diameter, and with 1 mm distance between thewalls. A ring of Celgard, 5 micrometers thick, is placed in between thetwo Kapton layers. A ring of Celgard, 5 micrometers thick and ¾ inchoutside diameter and ½ inch inside diameter, is placed in between theKapton layer next to lithium metal film anode and the Li electrode. ALISICON layer, 25 micrometer thick and ¾ inch diameter is placed betweenthe second Kapton and the air carbon-cathode. The electrolyte on the Liside of the LISICON is LiClO₄ in a combination of EC-DMC-PC-DME. Theelectrolyte on the air cathode side of LISICON is an aqueouselectrolyte.

Example H: In this example, two layers of PE films, each 5 micrometersthick and ¾ inch diameter are used for the separator system. Each layeris perforated with Cartesian (vertical-horizontal) periodic holes, each0.1 mm diameter, and with 0.1 mm distance between the walls. A LISICONlayer, 25 micrometer thick and ¾ inch diameter is placed between thesecond PE and the air carbon-cathode. The electrolyte on the Li side ofthe LISICON is LiPF6 in a combination of EC-DMC-PC-DME. The electrolyteon the air cathode side of LISICON is an aqueous electrolyte.

Example I: In this example, two layers of stainless steel, each 5micrometers thick, are used. The steel layers are coated with a verythin electronically isolating layer (here 1 micrometer thick Teflon) onthe inside faces (sides against the closer electrode). Each layer isperforated with Cartesian (vertical-horizontal) periodic holes, each 0.1mm diameter, and with 0.1 mm distance between the walls. A layer ofCelgard, 5 micrometers, is placed in between the two stainless steellayers. A layer of Celgard 5 micrometers is placed in between eachstainless steel layer and the adjacent electrode. The electrodes arepartially lithiated Si and partially lithiated sulfur. The battery withthis separator is expected to show higher cycle life andcharge-discharge (power) rates.

Example J: In this example, two layers of stainless steel, each 5micrometers thick, are used. The steel layers are coated with a verythin electronically isolating layer of 1 micrometer thick Teflon on theinside surfaces (the sides against the closer electrodes) and with a 1micrometer thick polyethylene glycol on the outside surface (the sidesfacing the closer electrodes). Each layer is perforated with Cartesian(vertical-horizontal) periodic holes, each 0.1 mm diameter, and with 0.1mm distance between the walls. A layer of cellulose separator, 5micrometers, is placed in between the two stainless steel layers. Alayer of cellulose separator, 5 micrometers, is placed in between eachstainless steel layer and the adjacent electrode. The electrodes are Limetal and sulfur. It is expected that the polyethylene glycol coatingincreases the cycle life of the battery.

Example K: In this example, two layers of polyimide films, each 5micrometers thick and ¾ inch diameter, are used for the separatorsystem. Each layer is perforated with Cartesian (vertical-horizontal)periodic holes, each 0.1 mm diameter, and with 0.1 mm distance betweenthe walls. A ring of microporous PE/PP/PE, 5 micrometers thick, isplaced in between the two polyimide layers. A ring of microporousPE/PP/PE, 5 micrometers thick and ¾ inch outside diameter and ½ inchinside diameter, is placed in between each polyimide layer and theadjacent electrode. The electrodes are Zinc anode and carbon based aircathode. The electrolyte is aqueous 6M NaOH.

Example L: In this example, two layers of hard PP films, each 5micrometers thick and ¾ inch diameter, are used for the separatorsystem. Each layer is perforated with Cartesian (vertical-horizontal)periodic holes, each 0.1 mm diameter. The electrodes are Zinc anode andcarbon based air cathode. The electrolyte is aqueous 6M KOH.

Example M: In this example, two layers of aluminum oxide films, each 5micrometers thick and ¾ inch diameter, are used for the separatorsystem. Each layer is perforated with an arbitrary pattern of holes thatare each 40% porous and when put on top of each other give less than 5%overlap of the hole patterns, each 0.1 mm diameter, and with 0.1 mmdistance between the walls. A ring of microporous polyester, 5micrometers thick, is placed in between the two aluminum oxide layers. Aring of microporous polyester, 5 micrometers thick and ¾ inch outsidediameter and ½ inch inside diameter, is placed in between each aluminumoxide layer and the adjacent electrode. The electrodes are Zinc anodeand carbon based air cathode. The electrolyte is aqueous 6M KOH.

Example N: In this example, two layers of hard polyester films, each 25micrometers thick and ¾ inch diameter, are used for the separatorsystem. Each layer is perforated with an arbitrary pattern of holes thatare each 40% porous and when put on top of each other give less than 5%overlap of the hole patterns, each 1 mm diameter, and with 1 mm distancebetween the walls. A ring of microporous polyester, 25 micrometersthick, is placed in between the two hard polyester layers. A ring ofmicroporous polyester, 25 micrometers thick and ¾ inch outside diameterand ½ inch inside diameter, is placed in between each hard polyesterlayer and the adjacent electrode. The electrodes are LiFePO₄ and siliconfilms. The electrolyte is ionic liquid.

Example O: In this example, two layers of Kapton films coated withpolyethylene glycol, each 5 micrometers thick and ¾ inch diameter, areused for the separator system. Each layer is perforated with Cartesian(vertical-horizontal) periodic holes, each 0.01 mm diameter, and with0.01 mm distance between the walls. A ring of Celgard, 5 micrometersthick, is placed in between the two Kapton layers. A ring of Celgard, 5micrometers thick and ¾ inch outside diameter and ½ inch insidediameter, is placed in between each Kapton layer and the adjacentelectrode. The electrodes are Sulfur and Lithium metal films. Theelectrolyte is a polymer electrolyte.

Example P: In this example, two layers of PP films, each 5 micrometersthick and ¾ inch diameter, are used for the separator system. Each layeris perforated with Cartesian (vertical-horizontal) periodic holes, each0.001 mm diameter, and with 0.001 mm distance between the walls. A ringof microporous polyester, 5 micrometers thick, is placed in between thetwo PP layers. A ring of microporous polyester, 5 micrometers thick and¾ inch outside diameter and ½ inch inside diameter, is placed in betweeneach PP layer and the adjacent electrode. The electrodes are NMC andcarbon films. The electrolyte is PEO.

Example Q. same as any of the above examples when the layers are attachéto each other by PEO and PvDFat some areas such as the outer part ofeach side.

Example R corresponds to Example G when the LISICON is 5 micrometers andis deposited on the hard layer on the air cathode side of thelithium-air cell.

In another Example, the porous patterned layers have the followingphysical dimensions, compositions and mechanical properties:

Thickness: 125 micron, 75 micron, 50 micron or 25 microns.

Tensile strength: 150 MPa isotropic (Celgard: 15 MPa TD; 150 MPA MD)

Porosity: 45%

Elastic modulus: 2 GPa

Yield strength: 50 MPa

Density: ˜1.3 g/cm³

MIT Folding Endurance: 10000 cycles

Elmendorf tear strength: 0.1 N

Graves tear strength: 15 N

Impact strength: 50 N·cm

30 mins @ 150 Celsius Shrinkage: 0.2 (Celgard: 5-10%)

Dielectric Strength ASTM D-149-91: 250 V/m

Dielectric constant: 3.5

Thermal coefficient of expansion: 20 ppm/Celsius.

Electrochemical cells comprising multilayer separators having porouspatterned layers with these properties exhibit useful performancecharacteristics. When tested a half cell [coin cells]: LiFePO₄|LP71|Li,for example, after 200 cycles: @ C/5 the capacity was ˜140 mAh/g; @C/2˜120 mAh/g. Force-displacement testing using external pressure showedthat the cell did not short but stopped functioning. Analysis of theseparator system after 300 cycles at C/2 showed little to no degradationand the separator system was able to be used in another cell.

Tables 1 and 2 provide summary of the physical dimensions and propertiesof high mechanical strength layers and separator systems of certainembodiments of the invention.

TABLE 1 Physical dimensions and properties of the high mechanicalstrength layers Embodiment 1 Embodiment 2 Process Dry Dry Composition PE& PP & PET PE & PP & Kapton Thickness (um) 125 125 Porosity (%) 40 40Ionic Resistivity(Ω · cm) 1800 400 ionic Resistivity(Ω · cm2) 22.5 5Melt temperature(° C.) 135/165/300 135/165/300 Tensile strength, MD(Kg/cm2) 2000 2000 Tensile Strength, TD (Kg/cm2) 2000 2000 MIT FoldingEndurance (cycles) 10000 10000 Impact strength (N · cm) 50 50 Thermalshrinkage % 0.2 0.2

TABLE 2 Physical dimensions and properties of the separator systemsEstimated Length Measured between Misalignment resistance electrodesResistivity Resistivity information (Ω) (μm) (Ω · cm) (Ω · cm2) >90%misalignment 57 125 3238 40 <60% misalignment 32 125 1818 23

The resistivities of the separators in Table 2 were tested in 1 M LiPF₆EC:EMC (30:70 by volume. For electrochemical evaluation, ½″ coincellelectrochemical cells with Al—Al electrodes were used to characterizethe separators. The separators are made as celgard/perforatedKapton/celgard/perforated kapton/celgard, each 25 μm thick.

Example 4 Separators Comprising Thermally Conductive Layers, Such asCoated Metal Mesh

In some aspects, separator systems of the invention comprise one or moreporous patterned layers that are a coated metal layer, such as a metalmesh having an external insulating coating, such as Al coated with PP orAl coated with aluminum oxide or a thermally conductive ceramic such asAl₂O₃. Embodiments of this aspect are beneficial for increasing the lifeof a battery significantly. In an embodiment, for example, the metalmesh (Al, nickel, copper, stainless steel) has very high mechanicalstrength over a very wide temperature range; the metal separator is athermally conductive material that homogenizes the temperature of thecell and significantly enhances the safety and the life of the cell. Inan embodiment, the microporous layers of the separator are PTFE coated(or PP coated or PEO coated or Al₂O₃ coated or PET coated or PVDFcoated) aluminum mesh layers (e.g. Al mesh, 40% opening: 3 layers, 5micrometers each or 2 layers ⅓ mil each; in one embodiment, Al layersare coated with PTFE, e.g. 2 micrometers thick on each side. In anotherembodiment only the Al layer next to the anode is coated. In anotherembodiment, the Al layers are coated and the sides are provided incontact with the electrodes.

Example 5 A Novel Method in Making Thin Membranes: A Mesh or FiberSupported Ceramic Production and their Applications as Membranes, forExample as Solid Electrolytes in Electrochemical Cells Such as Li-AirBatteries or as Filters in Bio-Industry or Food Industry or Filtration

Background: Li-air and Li-Sulfur batteries have energy density order ofmagnitude higher than current batteries. One approach for making thesecells is using a semi-permeable membrane such as LISICON, which allowsionic transport but prevents any other material to pass, to protect theanode from contamination with the cathode materials or their impurities.Thick solid electrolyte membranes not only show higher ionic resistanceand cause energy and power loss, but also form cracks and loseconnections with electrodes in a few cycles. Especially, it iswell-known in solid mechanics that there is a critical thickness thatthinner than that the plastic deformation and cracks can be avoided.Thus, in order to have high energy efficiency, high power density, fastcharging and high cycle life, the protective membrane should be as thinas possible. Today, making ceramics such as LISICON membranes of 50micrometer thick or smaller is a major challenge; more often pinholesform in the process of making thin ceramics and thus small particles canpass through the holes, and the ceramic loses its functionality as asemi-permeable membrane. This example suggests a new approach in makingthin (less than 50 micrometer) and very thin (less than 5 micrometer)solid electrolytes, especially ceramics based solid electrolytes. Theapplications are vast and in many industries; for example, such asceramic membranes as solid electrolytes in electrochemical cells andceramic membranes as filters in drug industry or bioengineering industryor in food processing.

In some embodiments the membrane is a composite solid electrolyte/meshsystem or a composite solid electrolyte/fibers system in which thetoughness of the mesh or fibers prevents the cracks and pinholes in theceramic during fabrication of the membrane and during the operation ofit.

The mesh is optionally in a periodic format, occupying only a small partof the total mesh supported ceramic system. The mesh volume, forexample, can be only 5-15% of the volume of the ceramic part. Further,the mesh is optionally totally inside the ceramic part, or is optionallyexposed on one face of the ceramic or both faces.

The mesh or fiber materials preferably have good ductility and strengthsuch as made of metals or alloys such as stainless steel, aluminum,copper or their alloys. The mesh is optionally made of a polymer such asPE, PP, Kapton, PVdF, PVC or PMMA. The mesh is optionally made of aglassy material, such as aluminum oxide or Silicon oxide or titaniumoxide.

The solid electrolyte is optionally any solid electrolyte such asLISICON or NASICON or PEO. The solid electrolyte is optionally used inan electrochemical cell such as a battery or an electrochemicalcapacitor or a fuel cell or a flow battery.

The system of mesh or fiber supported solid electrolyte is usefulbecause making thin solid electrolytes is difficult due to thedifficulties in production of thin layers of ceramics. For example, thedifficulty can be because of cracks formation in the production process,such as pinholes creation in thin LISICON for Lithium batteryapplications such as Li-air batteries. The mesh or fiber supportedsystem relaxes the stresses inside the ceramic, for example the solidelectrolyte such as LISICON, and thus prevents the cracks and holes suchas pinholes during the making of the ceramic. In some embodiments italso helps with relaxing the stresses due to the cycling and thisimproves the cycle life.

The system of mesh or fiber supported membrane is useful because makingthin membranes is difficult due to the difficulties in production ofthin layers of ceramics. For example, the difficulty can be because ofcracks formation in the production process, such as pinholes creation inthin membranes for filter applications such as in bio-industry or infood industry or in liquid filtration. The mesh or fiber supportedsystem relaxes the stresses inside the ceramics and thus prevents thecracks and holes such as pinholes during the making of the ceramic.

Other applications include fuel cell membranes or electrochemicalcapacitors or flow batteries or semis-solid batteries or cathode redoxflow batteries or solvated electrode batteries.

The method described in this example result in a mechanically strongmatrix where the mesh/fibers are mechanically tough, resulting in astrong and tough overall behavior of the system. This has beenunderstood in the overall behavior of systems such asmartensite/austenite systems; TRIP and maraging steel, recently inmetallic glasses, and in reinforced concreted, but has never beenapplied to the formation process and especially not in the formationprocess of thin membranes or thin ceramics that otherwise typically andfrequently suffer from pinholes and cracks during the manufacturing.

FIG. 31 shows an example of the application of the supported membrane inan electrochemical cell. In FIG. 31, The anode 3101 (such as lithium),is positioned adjacent to the anode organic electrolyte 3102 (such asLiClO₄ in PC-EC) and a separator (such as Celgard) and membrane 3103(such as comprising LISICON solid electrolyte) separates the anodeelectrolyte 3102 from a porous cathode (such as Sulfur or air cathode)and cathode electrolyte (such as aqueous electrolyte) 3104. Currentcollectors 3105 and 3106 are positioned in contact with anode 3101 andporous cathode/cathode electrolyte 3102.

FIG. 32 illustrates several possible configurations for construction ofa thin membrane, such as a separator/membrane 3103 as depicted in FIG.32. Here, ceramic 3207 is supported by mesh and/or fibers 3208.

Example 6 Active Membranes: Conductivity Assisting Membranes and theirUse as Active Separators in Electrochemical Cells Such as Batteries

Previous membranes and especially separators in electrochemical cellshave only been a passive component. Generally, separators inelectrochemical cells are electronically nonconductive components toelectronically separate the two opposite electrodes. This exampledescribes active membranes, especially as separators, in electrochemicalcells, such as in batteries.

For example a multi-layer membrane comprises two or more layers suchthat at least one of the layers at either of the ends of the membrane iselectronically conductive; and at least one of the middle layers iselectronically nonconductive such that there is no electronic connectionbetween the two outer faces of the membrane.

Optionally, some of the layers are deposited or coated on each other.Such a membrane is optionally useful as a separator in anelectrochemical cell. Optionally, some of the layers are deposited orcoated on another layer or on either of the electrodes. Optionally, theouter conductive layer results in a new electronic path for the outerparticles of the adjacent electrode and thus increases the electronicconductivity of the adjacent electrode materials.

Optionally separators of this example are used in an electrochemicalcell, such as where the electrode materials undergo shape change due tocharging-discharging, which can result in the loss of at least part ofthe electronic conductivity between the electrode materials and thecorresponding current collector.

Electrochemical cells useful for the described separators include, butare not limited to, lithium batteries. A lithium battery optionallyincludes a separator and optionally a silicon anode. Optionally, thecathode is lithium oxide or is sulfur or is carbon or air.Electrochemical cells useful for the described separators furtherinclude alkaline batteries and metal air batteries.

Optionally, in a multi-layer membrane, such as described above each ofthe conductive layers is a porous or perforated layer or a mesh made ofa metal such as stainless steel or aluminum or copper or Ni or tin.Optionally, the metallic layer is between an electrode and anelectronically non-conductive layer of the membrane. Optionally, thenon-conductive layer is a coating on one side of the metallic layer, forexample a polymer such as PTFE or PVDF or PEO or PMMA or PE or PP or PETor Al₂O₃.

Useful membranes include those where the total thickness of the membraneis less than 500 micrometers. Useful membranes include those where thetotal thickness of the membrane is less than 100 micrometers or lessthan 50 micrometers. Optionally, the total thickness of the membrane isless than 25 micrometers or less than 5 micrometers.

Optionally, the ionic resistance of a separator or membrane described inthis example is less than 10 Ωcm² or less than 1 Ωcm². Optionally, theporosity of a separator or membrane described in this example is atleast 30% or at least 70%. Optionally, the outer conductive layer of aseparator or membrane described in this example results in a change inelectric field at least in the vicinity of the corresponding electrode,for example when compared to a separator or membrane lacking the outerconductive layer. In some cases, the electric field modifications due tothe conductive layer of the separator results in a more uniform lithiumdeposition during charging and thus increase the performance, life cycleand efficiency of the electrochemical cell.

Optionally, membranes of this example are useful in electro-depositionssuch as in electro-depositing of a metal such as gold, silver or lithiumor zinc or copper or an alloy. Optionally, membranes of this example areuseful as a separator in an electrochemical cell, such as a rechargeablelithium metal battery.

FIG. 33A-33D depicts an example of the usage of the membrane as aseparator in an electrochemical cell such as in a battery. In FIGS.33A-33D the current collectors are identified as elements 3301A and3301B; the active electrode particles (e.g. Silicon) are identified aselements 3302; the conductive materials between active electrodeparticles, such as carbon black, are identified as elements 3303; aconventional separator is identified as elements 3304; a separator ofthis example is identified as element 3305; inactive (lost) electrodematerial due to the lost electronic connectivity is identified aselements 3306; the opposite electrode is identified as elements 3307;and electrolyte is identified as element 3308.

FIG. 33A depicts a schematic representation of the battery before use,where all of the electrode particles 3302 are electronically connected.FIG. 33B depicts a schematic representation of the battery aftercharging, where the electrode particles 3302 have a large shape change.FIG. 33C depicts a schematic representation of a battery with aconventional separator 3304 after several charge-discharge cycles,showing that some of the electrode particles have lost their electronicconnection with the current collector and thus are inactive electrodeparticles 3306. FIG. 33D depicts a schematic representation of a batteryincluding an electronically conductive separator 3305 in place ofconventional separator 3304 after several charge-discharge cycles,showing that some of the electrode particles have lost theirconventional electronic connection with the current collector butelectronically conductive separator 3305 provides a new path for some ofthe electrode particles 3303. Arrows indicate a path for electrontransfer from these particles to the current collector alongelectronically conductive separator 3305.

The new batteries described in this example are not limited toconventional parallel plate batteries. An example of such a battery wasmade by using the 3-d battery structure of the inventor, described inU.S. Patent Publication US 2012/0077095. 3 layers of LiCoO₂ cathode fromMTI, 2 cm×2 cm×0.2 mm, were put on top of each other and were perforatedto make periodic holes of 1 mm. Then rings of PE polymer, 0.025 mmthick, were put between them as electrolyte holders and the layers wereput in an aluminum tube 2 cm×2 cm×1 cm. Copper wires of about 0.75 mmdiameter were put through the holes and fixed from the top and bottom byguides. Electrolyte (mix of PC, EC, DMC and LiClO₄/LiPF₆) was added aselectrolyte. After fixing the cell and attaching in to a galvanostat,the cell was charged at rates starting at as low as 10 μA for up to fewdays. Lithium metal was deposited on the copper wire which formed theanode. After a few charge discharge cycles, called the formation of thecell, to stabilize the performance, the cell was ready to use. Aftercycling such a conventional cell at higher currents (for example 1 mA)the cell will short due to lithium dendrite formation on the copperwires and growing of such dendrites to the point that they touch theLiCoO₂ plates. Using the separator design of shifter-layers as discussedearlier prevents the short and improves the cycle life of the battery.

The separator efficiency in preventing dendrite shorting is also clearlyshown by making symmetric coin cells of lithium and cycling them at highcurrents. Results (experiment at room temperature, electrolyte: LP71from Merk) show that 0.75 mm thick disks of lithium foils can be cycledfor more than 500 cycles at rates of as high as 10 mA and at cyclingtime of 5 hours with no signs of shorting.

Example 7 Experimental Results for Electrochemical Cells Having anElectronically and Ionically Conductive Layer Positioned Adjacent to anElectrode

Experiment A: An electrochemical cell was constructed from a lithiumcobalt oxide cathode 0.100 mm thick and a Li metal anode 0.35 mm thick.The electrolyte used for the cell was Merck LP 71 (1 M LiPF₆ inEC-DC-DMC 1:1:1). A PE/PP/PE multilayer (Celgard 2325) 0.025 mm thickwas used as the separator. A conductive layer comprising Ni mesh (117.6)was placed between the Li anode and the separator. The cell was ½ inchsquare and made in house. The electrodes, the separator and theconductive layer were cut into ½ inch diameter disks.

The cell was constructed inside a glove box. The ½ inch square cell wasmade of Teflon. The lithium anode was made from lithium foil afterrinsing with DMC and hexane. LiCoO2 foil was used as the cathode. Thecell was constructed with the layers in the following order: wireheads/stainless steel disk/Li/Ni mesh layer/celgardseparator/LiCoO₂/aluminum foil. The electrolyte was used to oversaturatethe cell.

FIGS. 34, 35 and 36 show the cycling data, voltage vs time and currentvs time, of the cell. The cell was tested at room temperature, andvoltage range was set to 3-4.2 v.

Experiment B: An electrochemical cell was constructed from a lithiumcobalt oxide cathode 0.100 mm thick and a Li metal anode 0.35 mm thick.The electrolyte used for the cell was Merck LP 71 (1 M LiPF₆ inEC-DC-DMC 1:1:1). A PE/PP/PE multilayer (Celgard 2325) 0.025 mm thickwas used as the separator. A conductive layer comprising Cu mesh (117.6)was placed between the Li anode and the separator. The cell was ½ inchsquare and made in house. The electrodes, the separator and theconductive layer were cut into ½ inch diameter disks.

FIGS. 37, 38 and 39 show the cycling data, voltage vs time and currentvs time, of the cell. The cell was tested at room temperature, andvoltage range was set to 3-4.2 v.

Experiment C: Coin cells of size 2035 were made having a PE/PP/PEmultilayer separator (Celgard 2325) 0.025 mm thick. The electrolyte usedwas Merck LP 50 (1 M LiPF₆ in EC-EMC 1:1). A LiFePO4 cathode was usedand a graphite anode was used. A Ni mesh (117.6) was positioned betweenthe graphite anode and the separator.

FIGS. 40 and 41 show the cycling data, voltage vs time (top) and currentvs time (bottom), of the cells. The cell was tested at room temperature,and voltage range was set to 2.5-4.2 v.

Experiment D: Two coin cells of size 2035 were made having a PE/PP/PEmultilayer separator (Celgard 2325) 0.025 mm thick. The electrolyte usedwas Merck LP 50 (1 M LiPF₆ in EC-EMC 1:1). A LiFePO₄ cathode was usedand a Li anode was used. A Ni mesh (333) was positioned between theLiFePO₄ cathode and the separator.

FIGS. 42 and 43 show the cycling data, voltage vs time and current vstime, of the cell. The cell was tested at room temperature, and voltagerange was set to 2.5-4.2 v.

REFERENCES

-   U.S. Pat. Nos. 8,202,649, 8,288,034. U.S. Patent Application    Publication Nos. US 2012/0119155, US 2012/0219842, 2012/0183868.

STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS

All references throughout this application, for example patent documentsincluding issued or granted patents or equivalents; patent applicationpublications; and non-patent literature documents or other sourcematerial; are hereby incorporated by reference herein in theirentireties, as though individually incorporated by reference, to theextent each reference is at least partially not inconsistent with thedisclosure in this application (for example, a reference that ispartially inconsistent is incorporated by reference except for thepartially inconsistent portion of the reference).

The terms and expressions which have been employed herein are used asterms of description and not of limitation, and there is no intention inthe use of such terms and expressions of excluding any equivalents ofthe features shown and described or portions thereof, but it isrecognized that various modifications are possible within the scope ofthe invention claimed. Thus, it should be understood that although thepresent invention has been specifically disclosed by preferredembodiments, exemplary embodiments and optional features, modificationand variation of the concepts herein disclosed may be resorted to bythose skilled in the art, and that such modifications and variations areconsidered to be within the scope of this invention as defined by theappended claims. The specific embodiments provided herein are examplesof useful embodiments of the present invention and it will be apparentto one skilled in the art that the present invention may be carried outusing a large number of variations of the devices, device components,methods steps set forth in the present description. As will be obviousto one of skill in the art, methods and devices useful for the presentmethods can include a large number of optional composition andprocessing elements and steps.

All patents and publications mentioned in the specification areindicative of the levels of skill of those skilled in the art to whichthe invention pertains. References cited herein are incorporated byreference herein in their entirety to indicate the state of the art, insome cases as of their filing date, and it is intended that thisinformation can be employed herein, if needed, to exclude (for example,to disclaim) specific embodiments that are in the prior art. Forexample, when a compound is claimed, it should be understood thatcompounds known in the prior art, including certain compounds disclosedin the references disclosed herein (particularly in referenced patentdocuments), are not intended to be included in the claim.

When a group of substituents is disclosed herein, it is understood thatall individual members of those groups and all subgroups and classesthat can be formed using the substituents are disclosed separately. Whena Markush group or other grouping is used herein, all individual membersof the group and all combinations and subcombinations possible of thegroup are intended to be individually included in the disclosure. Asused herein, “and/or” means that one, all, or any combination of itemsin a list separated by “and/or” are included in the list; for example“1, 2 and/or 3” is equivalent to “‘1’ or ‘2’ or ‘3’ or ‘1 and 2’ or ‘1and 3’ or ‘2 and 3’ or ‘1, 2 and 3’”.

Every formulation or combination of components described or exemplifiedcan be used to practice the invention, unless otherwise stated. Specificnames of materials are intended to be exemplary, as it is known that oneof ordinary skill in the art can name the same material differently. Oneof ordinary skill in the art will appreciate that methods, deviceelements, starting materials, and synthetic methods other than thosespecifically exemplified can be employed in the practice of theinvention without resort to undue experimentation. All art-knownfunctional equivalents, of any such methods, device elements, startingmaterials, and synthetic methods are intended to be included in thisinvention. Whenever a range is given in the specification, for example,a temperature range, a time range, or a composition range, allintermediate ranges and subranges, as well as all individual valuesincluded in the ranges given are intended to be included in thedisclosure.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural reference unless thecontext clearly dictates otherwise. Thus, for example, reference to “acell” includes a plurality of such cells and equivalents thereof knownto those skilled in the art, and so forth. As well, the terms “a” (or“an”), “one or more” and “at least one” can be used interchangeablyherein. It is also to be noted that the terms “comprising”, “including”,and “having” can be used interchangeably. The expression “of any ofclaims XX-YY” (wherein XX and YY refer to claim numbers) is intended toprovide a multiple dependent claim in the alternative form, and in someembodiments is interchangeable with the expression “as in any one ofclaims XX-YY.”

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, the preferred methodsand materials are now described. Nothing herein is to be construed as anadmission that the invention is not entitled to antedate such disclosureby virtue of prior invention.

Whenever a range is given in the specification, for example, a range ofintegers, a temperature range, a time range, a composition range, orconcentration range, all intermediate ranges and subranges, as well asall individual values included in the ranges given are intended to beincluded in the disclosure. As used herein, ranges specifically includethe values provided as endpoint values of the range. As used herein,ranges specifically include all the integer values of the range. Forexample, a range of 1 to 100 specifically includes the end point valuesof 1 and 100. It will be understood that any subranges or individualvalues in a range or subrange that are included in the descriptionherein can be excluded from the claims herein.

As used herein, “comprising” is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended anddoes not exclude additional, unrecited elements or method steps. As usedherein, “consisting of” excludes any element, step, or ingredient notspecified in the claim element. As used herein, “consisting essentiallyof” does not exclude materials or steps that do not materially affectthe basic and novel characteristics of the claim. Any recitation hereinof the term “comprising”, particularly in a description of components ofa composition or in a description of elements of a device, is understoodto encompass those compositions and methods consisting essentially ofand consisting of the recited components or elements. The inventionillustratively described herein suitably may be practiced in the absenceof any element or elements, limitation or limitations which is notspecifically disclosed herein.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof, but it is recognizedthat various modifications are possible within the scope of theinvention claimed. Thus, it should be understood that although thepresent invention has been specifically disclosed by preferredembodiments and optional features, modification and variation of theconcepts herein disclosed may be resorted to by those skilled in theart, and that such modifications and variations are considered to bewithin the scope of this invention as defined by the appended claims.

1-195. (canceled)
 196. An electrochemical cell comprising: a positiveelectrode; a negative electrode; an ionically conductive andelectronically insulating separator positioned between said positiveelectrode and said negative electrode; a first electronically andionically conductive layer positioned between said positive electrodeand said separator and in electrical contact with said positiveelectrode or positioned between said negative electrode and saidseparator and in electrical contact with said negative electrode;wherein said first electronically and ionically conductive layercomprises an electronically conductive polymer or an electronicallyconductive ceramic; and one or more electrolytes positioned between saidpositive electrode and said negative electrode; wherein said one or moreelectrolytes are capable of conducting charge carriers; wherein saidfirst electronically and ionically conductive layer provides anelectronic conductivity greater than or equal to 1 S/cm and provides anionic resistance less than or equal to 10 Ωcm².
 197. The electrochemicalcell of claim 196, wherein said first electronically and ionicallyconductive layer comprises a porous layer, a perforated layer, or amesh.
 198. The electrochemical cell of claim 196, wherein said firstelectronically and ionically conductive layer conducts ions viatransport of said charge carriers of said electrolyte through one ormore apertures or pores in said first electronically and ionicallyconductive layer.
 199. The electrochemical cell of claim 196, whereinsaid first electronically and ionically conductive layer has a porositygreater than or equal to 30%.
 200. The electrochemical cell of claim196, wherein said first electronically and ionically conductive layerhas a porosity selected from the range of 30% to 90%.
 201. Theelectrochemical cell of claim 196, wherein said first electronically andionically conductive layer has a thickness less than or equal to 100 μm.202. The electrochemical cell of claim 196, wherein said firstelectronically and ionically conductive layer has a thickness selectedfrom the range of 10 nm to 100 μm.
 203. The electrochemical cell ofclaim 196, wherein said first electronically and ionically conductivelayer comprises a thin film structure or coating.
 204. Theelectrochemical cell of claim 203, wherein said thin film structure orcoating is deposited on at least one external surface of said positiveelectrode.
 205. The electrochemical cell of claim 203, wherein said thinfilm structure or coating is deposited on at least one external surfaceof said negative electrode.
 206. The electrochemical cell of claim 203,wherein said thin film structure or coating is deposited on at least oneexternal surface of said separator.
 207. The electrochemical cell ofclaim 196, wherein said first electronically and ionically conductivelayer is provided in physical contact with said separator.
 208. Theelectrochemical cell of claim 196, wherein said first electronically andionically conductive layer is in physical contact with said positiveelectrode or said negative electrode.
 209. The electrochemical cell ofclaim 196, wherein at least a portion of said first electronically andionically conductive layer is positioned within an active material ofsaid positive electrode or within an active material of said negativeelectrode.
 210. The electrochemical cell of claim 209, wherein saidportion of said first electronically and ionically conductive layer thatis positioned within said active material of said positive electrode orsaid active material of said negative electrode is not in physicalcontact with said separator.
 211. The electrochemical cell of claim 209,wherein said portion of said first electronically and ionicallyconductive layer that is positioned within said active material of saidpositive electrode or said active material of said negative electrode isin physical contact with a current collector of said positive electrodeor a current collector of said negative electrode.
 212. Theelectrochemical cell of claim 196, wherein said first electronically andionically conductive layer comprises poly(fluorene), polyphenylene,polypyrene, polyazulene, polynaphthalene, poly(acetylene),poly(p-phenylene vinylene), poly(pyrrole), polycarbazole, polyindole,polyazepine, polyaniline, poly(thiophene),poly(3,4-ethylenedioxythiophene), poly(p-phenylene sulfide),polyfluorene-based conducting polymer, PAN,Poly(9,9-dioctylfluorene-co-fluorenone),Poly(9,9-dioctylefluorene-co-fluorenone-co-methylbenzoic ester),polythiophene, polypyrrole, poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT:PSS), [(ferocenyl)amidopropyl]pyrrole,pyrrole, polypyrrole, polyaniline, polythiophene, polyfuran, Napon, orPVC or doped compositions thereof.
 213. The electrochemical cell ofclaim 196, wherein said first electronically and ionically conductivelayer comprises Indium tin oxide (ITO), lanthanum-doped strontiumtitanate (SLT), or yttrium-doped strontium titanate (SYT).
 214. Theelectrochemical cell of claim 196, wherein said first electronically andionically conductive layer increases an electronic conductivity of atleast a portion of said negative electrode or said positive electrode.215. The electrochemical cell of claim 196, further comprising a secondelectronically and ionically conductive layer; wherein said firstelectronically and ionically conductive layer is positioned inelectrical contact with said positive electrode and wherein said secondelectronically and ionically conductive layer is positioned inelectrical contact with said negative electrode, and wherein said firstand second electronically and ionically conductive layers are not inphysical or electrical contact with each other.
 216. The electrochemicalcell of claim 196, wherein said first electronically and ionicallyconductive layer provides an added path for electron transfer betweensaid positive electrode and a positive electrode current collector or anadded path for electron transfer between said negative electrode and anegative electrode current collector or wherein said firstelectronically and ionically conductive layer increases an electronicconductivity of at least a portion of said negative electrode or saidpositive electrode.
 217. The electrochemical cell of claim 196, whereinsaid first electronically and ionically conductive layer provides ahomogeneous electric field adjacent to and within said positiveelectrode or said negative electrode, thereby providing uniform iondeposition into said positive electrode or said negative electrode; orwherein said first electronically and ionically conductive layerprevents dendrite growth on or from said positive electrode or saidnegative electrode.
 218. The electrochemical cell of claim 196, whereinsaid first electronically and ionically conductive layer comprises anexternal current collector pole; or wherein said first electronicallyand ionically conductive layer reduces one of said positive electrodeand said negative electrode; or wherein said external current collectorpole oxidizes one of said positive electrode and said negativeelectrode.
 219. The electrochemical cell of claim 196, wherein saidelectrochemical cell comprises a secondary battery, a primary battery, aflow battery, a semi-solid battery, a fuel cell, an electrochemicalcapacitor.
 220. The electrochemical cell of claim 196, wherein saidelectrochemical cell comprises a lead acid battery, a lithium ionbattery, a lithium metal battery, a zinc battery, a lithium-air battery,a zinc-air battery, an aluminum-air battery, an iron-air battery, alithium-water battery, a silicon based battery, a sodium battery, amagnesium battery, a sodium ion battery, a magnesium ion battery, analkaline battery or a lead acid battery.